XenServer Documentation

3.1. Storage Overview

3.1.1. Storage Repositories (SRs)
3.1.2. Virtual Disk Images (VDIs)
3.1.3. Physical Block Devices (PBDs)
3.1.4. Virtual Block Devices (VBDs)
3.1.5. Summary of Storage objects
3.1.6. Virtual Disk Data Formats

3.2. Storage configuration

3.2.1. Creating Storage Repositories
3.2.2. Upgrading LVM storage from XenServer 5.0 or earlier
3.2.3. LVM performance considerations
3.2.4. Converting between VDI formats
3.2.5. Probing an SR
3.2.6. Storage Multipathing

3.3. Storage Repository Types

3.3.1. Local LVM
3.3.2. Local EXT3 VHD
3.3.3. udev
3.3.4. ISO
3.3.5. EqualLogic
3.3.6. NetApp
3.3.7. Software iSCSI Support
3.3.8. Managing Hardware Host Bus Adapters (HBAs)
3.3.9. LVM over iSCSI
3.3.10. NFS VHD
3.3.11. LVM over hardware HBA
3.3.12. Citrix StorageLink Gateway (CSLG) SRs

3.4. Managing Storage Repositories

3.4.1. Destroying or forgetting a SR
3.4.2. Introducing an SR
3.4.3. Resizing an SR
3.4.4. Converting local Fibre Channel SRs to shared SRs
3.4.5. Moving Virtual Disk Images (VDIs) between SRs
3.4.6. Adjusting the disk IO scheduler

3.5. Virtual disk QoS settings

This chapter discusses the framework for storage abstractions. It describes the way physical storage hardware of various kinds is mapped to VMs, and the software objects used by the XenServer host API to perform storage-related tasks. Detailed sections on each of the supported storage types include procedures for creating storage for VMs using the CLI, with type-specific device configuration options, generating snapshots for backup purposes and some best practices for managing storage in XenServer host environments. Finally, the virtual disk QoS (quality of service) settings are described.

3.1. Storage Overview

This section explains what the XenServer storage objects are and how they are related to each other.

3.1.1. Storage Repositories (SRs)

XenServer defines a container called a storage repository (SR) to describe a particular storage target, in which Virtual Disk Images (VDIs) are stored. A VDI is a disk abstraction which contains the contents of a virtual disk.

The interface to storage hardware allows VDIs to be supported on a large number of SR types. The XenServer SR is very flexible, with built-in support for IDE, SATA, SCSI and SAS drives locally connected, and iSCSI, NFS, SAS and Fibre Channel remotely connected. The SR and VDI abstractions allow advanced storage features such as sparse provisioning, VDI snapshots, and fast cloning to be exposed on storage targets that support them. For storage subsystems that do not inherently support advanced operations directly, a software stack is provided based on Microsoft's Virtual Hard Disk (VHD) specification which implements these features.

Each XenServer host can use multiple SRs and different SR types simultaneously. These SRs can be shared between hosts or dedicated to particular hosts. Shared storage is pooled between multiple hosts within a defined resource pool. A shared SR must be network accessible to each host. All hosts in a single resource pool must have at least one shared SR in common.

SRs are storage targets containing virtual disk images (VDIs). SR commands provide operations for creating, destroying, resizing, cloning, connecting and discovering the individual VDIs that they contain.

A storage repository is a persistent, on-disk data structure. For SR types that use an underlying block device, the process of creating a new SR involves erasing any existing data on the specified storage target. Other storage types such as NFS, Netapp, Equallogic and StorageLink SRs, create a new container on the storage array in parallel to existing SRs.

CLI operations to manage storage repositories are described in Section 8.4.14, “SR commands”.

3.1.2. Virtual Disk Images (VDIs)

Virtual Disk Images are a storage abstraction that is presented to a VM. VDIs are the fundamental unit of virtualized storage in XenServer. Similar to SRs, VDIs are persistent, on-disk objects that exist independently of XenServer hosts. CLI operations to manage VDIs are described in Section 8.4.20, “VDI commands”. The actual on-disk representation of the data differs by the SR type and is managed by a separate storage plugin interface for each SR, called the SM API.

3.1.3. Physical Block Devices (PBDs)

Physical Block Devices represent the interface between a physical server and an attached SR. PBDs are connector objects that allow a given SR to be mapped to a XenServer host. PBDs store the device configuration fields that are used to connect to and interact with a given storage target. For example, NFS device configuration includes the IP address of the NFS server and the associated path that the XenServer host mounts. PBD objects manage the run-time attachment of a given SR to a given XenServer host. CLI operations relating to PBDs are described in Section 8.4.10, “PBD commands”.

3.1.4. Virtual Block Devices (VBDs)

Virtual Block Devices are connector objects (similar to the PBD described above) that allows mappings between VDIs and VMs. In addition to providing a mechanism for attaching (also called plugging) a VDI into a VM, VBDs allow for the fine-tuning of parameters regarding QoS (quality of service), statistics, and the bootability of a given VDI. CLI operations relating to VBDs are described in Section 8.4.19, “VBD commands”.

3.1.5. Summary of Storage objects

The following image is a summary of how the storage objects presented so far are related:

Graphical overview of storage repositories and related objects

3.1.6. Virtual Disk Data Formats

In general, there are three types of mapping of physical storage to a VDI:

File-based VHD on a Filesystem; VM images are stored as thin-provisioned VHD format files on either a local non-shared Filesystem (EXT type SR) or a shared NFS target (NFS type SR)
Logical Volume-based VHD on a LUN; The default XenServer blockdevice-based storage inserts a Logical Volume manager on a disk, either a locally attached device (LVM type SR) or a SAN attached LUN over either Fibre Channel (LVMoHBA type SR), iSCSI (LVMoISCSI type SR) or SAS (LVMoHBA type Sr). VDIs are represented as volumes within the Volume manager and stored in VHD format to allow thin provisioning of reference nodes on snapshot and clone.
LUN per VDI; LUNs are directly mapped to VMs as VDIs by SR types that provide an array-specific plugin (Netapp, Equallogic or StorageLink type SRs). The array storage abstraction therefore matches the VDI storage abstraction for environments that manage storage provisioning at an array level.

3.1.6.1. VHD-based VDIs

VHD files may be chained, allowing two VDIs to share common data. In cases where a VHD-backed VM is cloned, the resulting VMs share the common on-disk data at the time of cloning. Each proceeds to make its own changes in an isolated copy-on-write (CoW) version of the VDI. This feature allows VHD-based VMs to be quickly cloned from templates, facilitating very fast provisioning and deployment of new VMs.

The VHD format used by LVM-based and File-based SR types in XenServer uses sparse provisioning. The image file is automatically extended in 2MB chunks as the VM writes data into the disk. For File-based VHD, this has the considerable benefit that VM image files take up only as much space on the physical storage as required. With LVM-based VHD the underlying logical volume container must be sized to the virtual size of the VDI, however unused space on the underlying CoW instance disk is reclaimed when a snapshot or clone occurs. The difference between the two behaviours can be characterised in the following way:

For LVM-based VHDs, the difference disk nodes within the chain consume only as much data as has been written to disk but the leaf nodes (VDI clones) remain fully inflated to the virtual size of the disk. Snapshot leaf nodes (VDI snapshots) remain deflated when not in use and can be attached Read-only to preserve the deflated allocation. Snapshot nodes that are attached Read-Write will be fully inflated on attach, and deflated on detach.
For file-based VHDs, all nodes consume only as much data as has been written, and the leaf node files grow to accommodate data as it is actively written. If a 100GB VDI is allocated for a new VM and an OS is installed, the VDI file will physically be only the size of the OS data that has been written to the disk, plus some minor metadata overhead.

When cloning VMs based off a single VHD template, each child VM forms a chain where new changes are written to the new VM, and old blocks are directly read from the parent template. If the new VM was converted into a further template and more VMs cloned, then the resulting chain will result in degraded performance. XenServer supports a maximum chain length of 30, but it is generally not recommended that you approach this limit without good reason. If in doubt, you can always "copy" the VM using XenServer or the vm-copy command, which resets the chain length back to 0.

3.1.6.1.1. VHD Chain Coalescing

VHD images support chaining, which is the process whereby information shared between one or more VDIs is not duplicated. This leads to a situation where trees of chained VDIs are created over time as VMs and their associated VDIs get cloned. When one of the VDIs in a chain is deleted, XenServer rationalizes the other VDIs in the chain to remove unnecessary VDIs.

This coalescing process runs asynchronously. The amount of disk space reclaimed and the time taken to perform the process depends on the size of the VDI and the amount of shared data. Only one coalescing process will ever be active for an SR. This process thread runs on the SR master host.

If you have critical VMs running on the master server of the pool and experience occasional slow IO due to this process, you can take steps to mitigate against this:

Migrate the VM to a host other than the SR master
Set the disk IO priority to a higher level, and adjust the scheduler. See Section 3.5, “Virtual disk QoS settings” for more information.

3.1.6.1.2. Space Utilisation

Space utilisation is always reported based on the current allocation of the SR, and may not reflect the amount of virtual disk space allocated. The reporting of space for LVM-based SRs versus File-based SRs will also differ given that File-based VHD supports full thin provisioning, while the underlying volume of an LVM-based VHD will be fully inflated to support potential growth for writeable leaf nodes. Space utilisation reported for the SR will depend on the number of snapshots, and the amount of difference data written to a disk between each snapshot.

LVM-based space utilisation differs depending on whether an LVM SR is upgraded vs created as a new SR in XenServer. Upgraded LVM SRs will retain a base node that is fully inflated to the size of the virtual disk, and any subsequent snapshot or clone operations will provision at least one additional node that is fully inflated. For new SRs, in contrast, the base node will be deflated to only the data allocated in the VHD overlay.

When VHD-based VDIs are deleted, the space is marked for deletion on disk. Actual removal of allocated data may take some time to occur as it is handled by the coalesce process that runs asynchronously and independently for each VHD-based SR.

3.1.6.2. LUN-based VDIs

Mapping a raw LUN as a Virtual Disk image is typically the most high-performance storage method. For administrators that want to leverage existing storage SAN infrastructure such as Netapp, Equallogic or StorageLink accessible arrays, the array snapshot, clone and thin provisioning capabilities can be exploited directly using one of the array specific adapter SR types (Netapp, Equallogic or StorageLink). The virtual machine storage operations are mapped directly onto the array APIs using a LUN per VDI representation. This includes activating the data path on demand such as when a VM is started or migrated to another host.

Managed NetApp LUNs are accessible using the NetApp SR driver type, and are hosted on a Network Appliance device running a version of Ontap 7.0 or greater. LUNs are allocated and mapped dynamically to the host using the XenServer host management framework.

EqualLogic storage is accessible using the EqualLogic SR driver type, and is hosted on an EqualLogic storage array running a firmware version of 4.0 or greater. LUNs are allocated and mapped dynamically to the host using the XenServer host management framework.

For further information on StorageLink supported array systems and the various capabilities in each case, please refer to the StorageLink documentation directly.

3.2. Storage configuration

This section covers creating storage repository types and making them available to a XenServer host. The examples provided pertain to storage configuration using the CLI, which provides the greatest flexibility. See the XenCenter Help for details on using the New Storage Repository wizard.

3.2.1. Creating Storage Repositories

This section explains how to create Storage Repositories (SRs) of different types and make them available to a XenServer host. The examples provided cover creating SRs using the xe CLI. See the XenCenter help for details on using the New Storage Repository wizard to add SRs using XenCenter.

Note

Local SRs of type lvm and ext can only be created using the xe CLI. After creation all SR types can be managed by either XenCenter or the xe CLI.

There are two basic steps involved in creating a new storage repository for use on a XenServer host using the CLI:

Probe the SR type to determine values for any required parameters.
Create the SR to initialize the SR object and associated PBD objects, plug the PBDs, and activate the SR.

These steps differ in detail depending on the type of SR being created. In all examples the sr-create command returns the UUID of the created SR if successful.

SRs can also be destroyed when no longer in use to free up the physical device, or forgotten to detach the SR from one XenServer host and attach it to another. See Section 3.4.1, “Destroying or forgetting a SR” for details.

3.2.2. Upgrading LVM storage from XenServer 5.0 or earlier

See the XenServer Installation Guide for information on upgrading LVM storage to enable the latest features. Local, LVM on iSCSI, and LVM on HBA storage types from older (XenServer 5.0 and before) product versions will need to be upgraded before they will support snapshot and fast clone.

Note

Upgrade is a one-way operation so Citrix recommends only performing the upgrade when you are certain the storage will no longer need to be attached to a pool running an older software version.

3.2.3. LVM performance considerations

The snapshot and fast clone functionality provided in XenServer 5.5 and later for LVM-based SRs comes with an inherent performance overhead. In cases where optimal performance is desired, XenServer supports creation of VDIs in the raw format in addition to the default VHD format. The XenServer snapshot functionality is not supported on raw VDIs.

Note

Non-transportable snapshots using the default Windows VSS provider will work on any type of VDI.

Warning

Do not try to snapshot a VM that has type=raw disks attached. This could result in a partial snapshot being created. In this situation, you can identify the orphan snapshot VDIs by checking the snapshot-of field and then deleting them.

3.2.3.1. VDI types

In general, VHD format VDIs will be created. You can opt to use raw at the time you create the VDI; this can only be done using the xe CLI. After software upgrade from a previous XenServer version, existing data will be preserved as backwards-compatible raw VDIs but these are special-cased so that snapshots can be taken of them once you have allowed this by upgrading the SR. Once the SR has been upgraded and the first snapshot has been taken, you will be accessing the data through a VHD format VDI.

To check if an SR has been upgraded, verify that its sm-config:use_vhd key is true. To check if a VDI was created with type=raw, check its sm-config map. The sr-param-list and vdi-param-list xe commands can be used respectively for this purpose.

3.2.3.2. Creating a raw virtual disk using the xe CLI

Run the following command to create a VDI given the UUID of the SR you want to place the virtual disk in:
```
xe vdi-create sr-uuid=<sr-uuid> type=user virtual-size=<virtual-size> name-label=<VDI name>
```
Attach the new virtual disk to a VM and use your normal disk tools within the VM to partition and format, or otherwise make use of the new disk. You can use the vbd-create command to create a new VBD to map the virtual disk into your VM.

3.2.4. Converting between VDI formats

It is not possible to do a direct conversion between the raw and VHD formats. Instead, you can create a new VDI (either raw, as described above, or VHD if the SR has been upgraded or was created on XenServer 5.5 or later) and then copy data into it from an existing volume. Citrix recommends that you use the xe CLI to ensure that the new VDI has a virtual size at least as big as the VDI you are copying from (by checking its virtual-size field, for example by using the vdi-param-list command). You can then attach this new VDI to a VM and use your preferred tool within the VM (standard disk management tools in Windows, or the dd command in Linux) to do a direct block-copy of the data. If the new volume is a VHD volume, it is important to use a tool that can avoid writing empty sectors to the disk so that space is used optimally in the underlying storage repository — in this case a file-based copy approach may be more suitable.

3.2.5. Probing an SR

The sr-probe command can be used in two ways:

To identify unknown parameters for use in creating a SR.
To return a list of existing SRs.

In both cases sr-probe works by specifying an SR type and one or more device-config parameters for that SR type. When an incomplete set of parameters is supplied the sr-probe command returns an error message indicating parameters are missing and the possible options for the missing parameters. When a complete set of parameters is supplied a list of existing SRs is returned. All sr-probe output is returned as XML.

For example, a known iSCSI target can be probed by specifying its name or IP address, and the set of IQNs available on the target will be returned:

xe sr-probe type=lvmoiscsi device-config:target=<192.168.1.10>

Error code: SR_BACKEND_FAILURE_96
Error parameters: , The request is missing or has an incorrect target IQN parameter, \
<?xml version="1.0" ?>
<iscsi-target-iqns>
    <TGT>
        <Index>
            0
        </Index>
        <IPAddress>
            192.168.1.10
        </IPAddress>
        <TargetIQN>
            iqn.192.168.1.10:filer1
        </TargetIQN>
    </TGT>
</iscsi-target-iqns>

Probing the same target again and specifying both the name/IP address and desired IQN returns the set of SCSIids (LUNs) available on the target/IQN.

xe sr-probe type=lvmoiscsi device-config:target=192.168.1.10  \ 
device-config:targetIQN=iqn.192.168.1.10:filer1

Error code: SR_BACKEND_FAILURE_107
Error parameters: , The SCSIid parameter is missing or incorrect, \
<?xml version="1.0" ?>
<iscsi-target>
    <LUN>
        <vendor>
			IET
        </vendor>
        <LUNid>
            0
        </LUNid>
        <size>
            42949672960
        </size>
        <SCSIid>
            149455400000000000000000002000000b70200000f000000
        </SCSIid>
    </LUN>
</iscsi-target>

Probing the same target and supplying all three parameters will return a list of SRs that exist on the LUN, if any.

xe sr-probe type=lvmoiscsi device-config:target=192.168.1.10  \ 
device-config:targetIQN=192.168.1.10:filer1 \
device-config:SCSIid=149455400000000000000000002000000b70200000f000000

<?xml version="1.0" ?>
<SRlist>
    <SR>
        <UUID>
            3f6e1ebd-8687-0315-f9d3-b02ab3adc4a6
        </UUID>
        <Devlist>
            /dev/disk/by-id/scsi-149455400000000000000000002000000b70200000f000000
        </Devlist>
    </SR>
</SRlist>

The following parameters can be probed for each SR type:

SR type	device-config parameter, in order of dependency	Can be probed?	Required for sr-create?
lvmoiscsi	target	No	Yes
	chapuser	No	No
	chappassword	No	No
	targetIQN	Yes	Yes
	SCSIid	Yes	Yes
lvmohba	SCSIid	Yes	Yes
netapp	target	No	Yes
	username	No	Yes
	password	No	Yes
	chapuser	No	No
	chappassword	No	No
	aggregate	No^[a]	Yes
	FlexVols	No	No
	allocation	No	No
	asis	No	No
nfs	server	No	Yes
	serverpath	Yes	Yes
lvm	device	No	Yes
ext	device	No	Yes
equallogic	target	No	Yes
	username	No	Yes
	password	No	Yes
	chapuser	No	No
	chappassword	No	No
	storagepool	No^[b]	Yes
cslg	target	No	Yes
	storageSystemId	Yes	Yes
	storagePoolId	Yes	Yes
	username	No	No ^[c]
	password	No	No ^[c]
	cslport	No	No ^[c]
	chapuser	No	No ^[c]
	chappassword	No	No ^[c]
	provision-type	Yes	No
	protocol	Yes	No
	provision-options	Yes	No
	raid-type	Yes	No
^[a]Aggregate probing is only possible at sr-create time. It needs to be done there so that the aggregate can be specified at the point that the SR is created. ^[b]Storage pool probing is only possible at sr-create time. It needs to be done there so that the aggregate can be specified at the point that the SR is created. ^[c]If the username, password, or port configuration of the StorageLink service are changed from the default value then the appropriate parameter and value must be specified.

3.2.6. Storage Multipathing

Dynamic multipathing support is available for Fibre Channel and iSCSI storage backends. By default, it uses round-robin mode load balancing, so both routes have active traffic on them during normal operation. You can enable multipathing in XenCenter or on the xe CLI.

Caution

Before attempting to enable multipathing, verify that multiple targets are available on your storage server. For example, an iSCSI storage backend queried for sendtargets on a given portal should return multiple targets, as in the following example:

iscsiadm -m discovery --type sendtargets --portal 192.168.0.161
192.168.0.161:3260,1 iqn.strawberry:litchie
192.168.0.204:3260,2 iqn.strawberry:litchie

To enable storage multipathing using the xe CLI

Unplug all PBDs on the host:
```
xe pbd-unplug uuid=<pbd_uuid>
```

Set the host's other-config:multipathing parameter:

xe host-param-set other-config:multipathing=true uuid=host_uuid

Set the host's other-config:multipathhandle parameter to dmp:

xe host-param-set other-config:multipathhandle=dmp uuid=host_uuid

If there are existing SRs on the host running in single path mode but that have multiple paths:
- Migrate or suspend any running guests with virtual disks in affected the SRs
- Unplug and re-plug the PBD of any affected SRs to reconnect them using multipathing:
```
xe pbd-plug uuid=<pbd_uuid>
```

To disable multipathing, first unplug your VBDs, set the host other-config:multipathing parameter to false and then replug your PBDs as described above. Do not modify the other-config:multipathhandle parameter as this will be done automatically.

Multipath support in XenServer is based on the device-mapper multipathd components. Activation and deactivation of multipath nodes is handled automatically by the Storage Manager API. Unlike the standard dm-multipath tools in linux, device mapper nodes are not automatically created for all LUNs on the system, and it is only when LUNs are actively used by the storage management layer that new device mapper nodes are provisioned. It is unnecessary therefore to use any of the dm-multipath CLI tools to query or refresh DM table nodes in XenServer. Should it be necessary to query the status of device-mapper tables manually, or list active device mapper multipath nodes on the system, use the mpathutil utility:

mpathutil list
mpathutil status

Unlike the standard dm-multipath tools in Linux, device mapper nodes are not automatically created for all LUNs on the system. As LUNs are actively used by the storage management layer, new device mapper nodes are provisioned. It is unnecessary to use any of the dm-multipath CLI tools to query or refresh DM table nodes in XenServer.

Note

Due to incompatibilities with the integrated multipath management architecture, the standard dm-multipath CLI utility should not be used with XenServer. Please use the mpathutil CLI tool for querying the status of nodes on the host.

Note

Multipath support in Equallogic arrays does not encompass Storage IO multipathing in the traditional sense of the term. Multipathing must be handled at the network/NIC bond level. Refer to the Equallogic documentation for information about configuring network failover for Equallogic SRs/LVMoISCSI SRs.

3.3. Storage Repository Types

The storage repository types supported in XenServer are provided by plug-ins in the control domain; these can be examined and plugins supported by third parties can be added to the /opt/xensource/sm directory. Modification of these files is unsupported, but visibility of these files may be valuable to developers and power users. New storage manager plugins placed in this directory are automatically detected by XenServer. Use the sm-list command (see Section 8.4.13, “Storage Manager commands”) to list the available SR types .

New storage repositories are created using the New Storage wizard in XenCenter. The wizard guides you through the various probing and configuration steps. Alternatively, use the sr-create command. This command creates a new SR on the storage substrate (potentially destroying any existing data), and creates the SR API object and a corresponding PBD record, enabling VMs to use the storage. On successful creation of the SR, the PBD is automatically plugged. If the SR shared=true flag is set, a PBD record is created and plugged for every XenServer Host in the resource pool.

All XenServer SR types support VDI resize, fast cloning and snapshot. SRs based on the LVM SR type (local, iSCSI, or HBA) provide thin provisioning for snapshot and hidden parent nodes. The other SR types support full thin provisioning, including for virtual disks that are active.

Note

Automatic LVM metadata archiving is disabled by default. This does not prevent metadata recovery for LVM groups.

Warning

When VHD VDIs are not attached, for example in the case of a VDI snapshot, they are stored by default thinly-provisioned. Because of this it is imperative to ensure that there is sufficient disk-space available for the VDI to become thickly provisioned when attempting to attach it. VDI clones, however, are thickly-provisioned.

The maximum supported VDI sizes are:

Storage type	Maximum VDI size
EXT3	2TB
LVM	2TB
Netapp	2TB
EqualLogic	15TB
ONTAP(NetApp)	12TB

3.3.1. Local LVM

The Local LVM type presents disks within a locally-attached Volume Group.

By default, XenServer uses the local disk on the physical host on which it is installed. The Linux Logical Volume Manager (LVM) is used to manage VM storage. A VDI is implemented in VHD format in an LVM logical volume of the specified size.

XenServer versions prior to 5.5.0 did not use the VHD format and will remain in legacy mode. See Section 3.2.2, “Upgrading LVM storage from XenServer 5.0 or earlier” for information about upgrading a storage repository to the new format.

3.3.1.1. Creating a local LVM SR (lvm)

Device-config parameters for lvm SRs are:

Parameter Name	Description	Required?
Device	device name on the local host to use for the SR	Yes

To create a local lvm SR on /dev/sdb use the following command.

xe sr-create host-uuid=<valid_uuid> content-type=user \
name-label=<"Example Local LVM SR"> shared=false \
device-config:device=/dev/sdb type=lvm

3.3.2. Local EXT3 VHD

The Local EXT3 VHD type represents disks as VHD files stored on a local path.

Local disks can also be configured with a local EXT SR to serve VDIs stored in the VHD format. Local disk EXT SRs must be configured using the XenServer CLI.

By definition, local disks are not shared across pools of XenServer host. As a consequence, VMs whose VDIs are stored in SRs on local disks are not agile -- they cannot be migrated between XenServer hosts in a resource pool.

3.3.2.1. Creating a local EXT3 SR (ext)

Device-config parameters for ext SRs:

Parameter Name	Description	Required?
Device	device name on the local host to use for the SR	Yes

To create a local ext SR on /dev/sdb use the following command:

xe sr-create host-uuid=<valid_uuid> content-type=user \
name-label=<"Example Local EXT3 SR"> shared=false \
device-config:device=/dev/sdb type=ext

3.3.3. udev

The udev type represents devices plugged in using the udev device manager as VDIs.

XenServer has two SRs of type udev that represent removable storage. One is for the CD or DVD disk in the physical CD or DVD-ROM drive of the XenServer host. The other is for a USB device plugged into a USB port of the XenServer host. VDIs that represent the media come and go as disks or USB sticks are inserted and removed.

3.3.4. ISO

The ISO type handles CD images stored as files in ISO format. This SR type is useful for creating shared ISO libraries.

3.3.5. EqualLogic

The EqualLogic SR type maps LUNs to VDIs on a EqualLogic array group, allowing for the use of fast snapshot and clone features on the array.

If you have access to an EqualLogic filer, you can configure a custom EqualLogic storage repository for VM storage on you XenServer deployment. This allows the use of the advanced features of this filer type. Virtual disks are stored on the filer using one LUN per virtual disk. Using this storage type will enable the thin provisioning, snapshot, and fast clone features of this filer.

Consider your storage requirements when deciding whether to use the specialized SR plugin, or to use the generic LVM/iSCSI storage backend. By using the specialized plugin, XenServer will communicate with the filer to provision storage. Some arrays have a limitation of seven concurrent connections, which may limit the throughput of control operations. Using the plugin will allow you to make use of the advanced array features, however, so will make backup and snapshot operations easier.

Warning

There are two types of administration accounts that can successfully access the EqualLogic SM plugin:

A group administration account which has access to and can manage the entire group and all storage pools.
A pool administrator account that can manage only the objects (SR and VDI snapshots) that are in the pool or pools assigned to the account.

3.3.5.1. Creating a shared EqualLogic SR

Device-config parameters for EqualLogic SRs:

Parameter Name	Description	Optional?
target	the IP address or hostname of the EqualLogic array that hosts the SR	no
username	the login username used to manage the LUNs on the array	no
password	the login password used to manage the LUNs on the array	no
storagepool	the storage pool name	no
chapuser	the username to be used for CHAP authentication	yes
chappassword	the password to be used for CHAP authentication	yes
allocation	specifies whether to use thick or thin provisioning. Default is thick. Thin provisioning reserves a minimum of 10% of volume space.	yes
snap-reserve-percentage	sets the amount of space, as percentage of volume reserve, to allocate to snapshots. Default is 100%.	yes
snap-depletion	sets the action to take when snapshot reserve space is exceeded. `volume-offline` sets the volume and all its snapshots offline. This is the default action. The `delete-oldest` action deletes the oldest snapshot until enough space is available for creating the new snapshot.	yes

Use the sr-create command to create an EqualLogic SR. For example:

xe sr-create host-uuid=<valid_uuid> content-type=user \
name-label=<"Example shared Equallogic SR"> \
shared=true device-config:target=<target_ip> \
device-config:username=<admin_username> \
device-config:password=<admin_password> \
device-config:storagepool=<my_storagepool> \
device-config:chapuser=<chapusername> \
device-config:chappassword=<chapuserpassword> \
device-config:allocation=<thick> \
type=equal

3.3.6. NetApp

The NetApp type maps LUNs to VDIs on a NetApp server, enabling the use of fast snapshot and clone features on the filer.

Note

NetApp and EqualLogic SRs require a Citrix Essentials for XenServer license. To learn more about Citrix Essentials for XenServer and to find out how to upgrade, visit the Citrix website here.

If you have access to Network Appliance™ (NetApp) storage with sufficient disk space, running a version of Data ONTAP 7G (version 7.0 or greater), you can configure a custom NetApp storage repository for VM storage on your XenServer deployment. The XenServer driver uses the ZAPI interface to the storage to create a group of FlexVols that correspond to an SR. VDIs are created as virtual LUNs on the storage, and attached to XenServer hosts using an iSCSI data path. There is a direct mapping between a VDI and a raw LUN that does not require any additional volume metadata. The NetApp SR is a managed volume and the VDIs are the LUNs within the volume. VM cloning uses the snapshotting and cloning capabilities of the storage for data efficiency and performance and to ensure compatibility with existing ONTAP management tools.

As with the iSCSI-based SR type, the NetApp driver also uses the built-in software initiator and its assigned host IQN, which can be modified by changing the value shown on the General tab when the storage repository is selected in XenCenter.

The easiest way to create NetApp SRs is to use XenCenter. See the XenCenter help for details. See Section 3.3.6.1, “Creating a shared NetApp SR over iSCSI” for an example of how to create them using the xe CLI.

FlexVols

NetApp uses FlexVols as the basic unit of manageable data. There are limitations that constrain the design of NetApp-based SRs. These are:

maximum number of FlexVols per filer
maximum number of LUNs per network port
maximum number of snapshots per FlexVol

Precise system limits vary per filer type, however as a general guide, a FlexVol may contain up to 200 LUNs, and provides up to 255 snapshots. Because there is a one-to-one mapping of LUNs to VDIs, and because often a VM will have more than one VDI, the resource limitations of a single FlexVol can easily be reached. Also, the act of taking a snapshot includes snapshotting all the LUNs within a FlexVol and the VM clone operation indirectly relies on snapshots in the background as well as the VDI snapshot operation for backup purposes.

There are two constraints to consider when mapping the virtual storage objects of the XenServer host to the physical storage. To maintain space efficiency it makes sense to limit the number of LUNs per FlexVol, yet at the other extreme, to avoid resource limitations a single LUN per FlexVol provides the most flexibility. However, because there is a vendor-imposed limit of 200 or 500 FlexVols, per filer (depending on the NetApp model), this creates a limit of 200 or 500 VDIs per filer and it is therefore important to select a suitable number of FlexVols taking these parameters into account.

Given these resource constraints, the mapping of virtual storage objects to the Ontap storage system has been designed in the following manner. LUNs are distributed evenly across FlexVols, with the expectation of using VM UUIDs to opportunistically group LUNs attached to the same VM into the same FlexVol. This is a reasonable usage model that allows a snapshot of all the VDIs in a VM at one time, maximizing the efficiency of the snapshot operation.

An optional parameter you can set is the number of FlexVols assigned to the SR. You can use between 1 and 32 FlexVols; the default is 8. The trade-off in the number of FlexVols to the SR is that, for a greater number of FlexVols, the snapshot and clone operations become more efficient, because there are fewer VMs backed off the same FlexVol. The disadvantage is that more FlexVol resources are used for a single SR, where there is a typical system-wide limitation of 200 for some smaller filers.

Aggregates

When creating a NetApp driver-based SR, you select an appropriate aggregate. The driver can be probed for non-traditional type aggregates, that is, newer-style aggregates that support FlexVols, and lists all aggregates available and the unused disk space on each.

Note

Aggregate probing is only possible at sr-create time so that the aggregate can be specified at the point that the SR is created, but is not probed by the sr-probe command.

Citrix strongly recommends that you configure an aggregate exclusively for use by XenServer storage, because space guarantees and allocation cannot be correctly managed if other applications are sharing the resource.

Thick or thin provisioning

When creating NetApp storage, you can also choose the type of space management used. By default, allocated space is thickly provisioned to ensure that VMs never run out of disk space and that all virtual allocation guarantees are fully enforced on the filer. Selecting thick provisioning ensures that whenever a VDI (LUN) is allocated on the filer, sufficient space is reserved to guarantee that it will never run out of space and consequently experience failed writes to disk. Due to the nature of the Ontap FlexVol space provisioning algorithms the best practice guidelines for the filer require that at least twice the LUN space is reserved to account for background snapshot data collection and to ensure that writes to disk are never blocked. In addition to the double disk space guarantee, Ontap also requires some additional space reservation for management of unique blocks across snapshots. The guideline on this amount is 20% above the reserved space. The space guarantees afforded by thick provisioning will reserve up to 2.4 times the requested virtual disk space.

The alternative allocation strategy is thin provisioning, which allows the administrator to present more storage space to the VMs connecting to the SR than is actually available on the SR. There are no space guarantees, and allocation of a LUN does not claim any data blocks in the FlexVol until the VM writes data. This might be appropriate for development and test environments where you might find it convenient to over-provision virtual disk space on the SR in the anticipation that VMs might be created and destroyed frequently without ever utilizing the full virtual allocated disk.

Warning

If you are using thin provisioning in production environments, take appropriate measures to ensure that you never run out of storage space. VMs attached to storage that is full will fail to write to disk, and in some cases may fail to read from disk, possibly rendering the VM unusable.

FAS Deduplication

FAS Deduplication is a NetApp technology for reclaiming redundant disk space. Newly-stored data objects are divided into small blocks, each block containing a digital signature, which is compared to all other signatures in the data volume. If an exact block match exists, the duplicate block is discarded and the disk space reclaimed. FAS Deduplication can be enabled on thin provisioned NetApp-based SRs and operates according to the default filer FAS Deduplication parameters, typically every 24 hours. It must be enabled at the point the SR is created and any custom FAS Deduplication configuration must be managed directly on the filer.

Access Control

Because FlexVol operations such as volume creation and volume snapshotting require administrator privileges on the filer itself, Citrix recommends that the XenServer host is provided with suitable administrator username and password credentials at configuration time. In situations where the XenServer host does not have full administrator rights to the filer, the filer administrator could perform an out-of-band preparation and provisioning of the filer and then introduce the SR to the XenServer host using XenCenter or the sr-introduce xe CLI command. Note, however, that operations such as VM cloning or snapshot generation will fail in this situation due to insufficient access privileges.

Licenses

You need to have an iSCSI license on the NetApp filer to use this storage repository type; for the generic plugins you need either an iSCSI or NFS license depending on the SR type being used.

Further information

For more information about NetApp technology, see the following links:

3.3.6.1. Creating a shared NetApp SR over iSCSI

Device-config parameters for netapp SRs:

Parameter Name	Description	Optional?
target	the IP address or hostname of the NetApp server that hosts the SR	no
port	the port to use for connecting to the NetApp server that hosts the SR. Default is port 80.	yes
usehttps	specifies whether to use a secure TLS-based connection to the NetApp server that hosts the SR [true\|false]. Default is false.	yes
username	the login username used to manage the LUNs on the filer	no
password	the login password used to manage the LUNs on the filer	no
aggregate	the aggregate name on which the FlexVol is created	Required for sr_create
FlexVols	the number of FlexVols to allocate to each SR	yes
chapuser	the username for CHAP authentication	yes
chappassword	the password for CHAP authentication	yes
allocation	specifies whether to provision LUNs using thick or thin provisioning. Default is thick	yes
asis	specifies whether to use FAS Deduplication if available. Default is false	yes

Setting the SR other-config:multiplier parameter to a valid value adjusts the default multiplier attribute. By default XenServer allocates 2.4 times the requested space to account for snapshot and metadata overhead associated with each LUN. To save disk space, you can set the multiplier to a value >= 1. Setting the multiplier should only be done with extreme care by system administrators who understand the space allocation constraints of the NetApp filer. If you try to set the amount to less then 1, for example, in an attempt to pre-allocate very little space for the LUN, the attempt will most likely fail.

Setting the SR other-config:enforce_allocation parameter to true resizes the FlexVols to precisely the amount specified by either the multiplier value above, or the default 2.4 value.

Note

This works on new VDI creation in the selected FlexVol, or on all FlexVols during an SR scan and overrides any manual size adjustments made by the administrator to the SR FlexVols.

To create a NetApp SR, use the following command.

xe sr-create host-uuid=<valid_uuid> content-type=user \
  name-label=<"Example shared NetApp SR"> shared=true \
  device-config:target=<192.168.1.10> device-config:username=<admin_username> \
  device-config:password=<admin_password> \
  type=netapp

3.3.6.2. Managing VDIs in a NetApp SR

Due to the complex nature of mapping VM storage objects onto NetApp storage objects such as LUNs, FlexVols and disk Aggregates, the plugin driver makes some general assumptions about how storage objects should be organized. The default number of FlexVols that are managed by an SR instance is 8, named XenStorage_<SR_UUID>_FV<#> where # is a value between 0 and the total number of FlexVols assigned. This means that VDIs (LUNs) are evenly distributed across any one of the FlexVols at the point that the VDI is instantiated. The only exception to this rule is for groups of VM disks which are opportunistically assigned to the same FlexVol to assist with VM cloning, and when VDIs are created manually but passed a vmhint flag that informs the backend of the FlexVol to which the VDI should be assigned. The vmhint may be a random string such as a uuid that is re-issued for all subsequent VDI creation operations to ensure grouping in the same FlexVol, or it can be a simple FlexVol number to correspond to the FlexVol naming convention applied on the Filer. Using either of the following 2 commands, a VDI created manually using the CLI can be assigned to a specific FlexVol:

xe vdi-create uuid=<valid_vdi_uuid> sr-uuid=<valid_sr_uuid> \
sm-config:vmhint=<valid_vm_uuid>

xe vdi-create uuid=<valid_vdi_uuid> sr-uuid=<valid_sr_uuid> \
sm-config:vmhint=<valid_flexvol_number>

3.3.6.3. Taking VDI snapshots with a NetApp SR

Cloning a VDI entails generating a snapshot of the FlexVol and then creating a LUN clone backed off the snapshot. When generating a VM snapshot you must snapshot each of the VMs disks in sequence. Because all the disks are expected to be located in the same FlexVol, and the FlexVol snapshot operates on all LUNs in the same FlexVol, it makes sense to re-use an existing snapshot for all subsequent LUN clones. By default, if no snapshot hint is passed into the backend driver it will generate a random ID with which to name the FlexVol snapshot. There is a CLI override for this value, passed in as an epochhint. The first time the epochhint value is received, the backend generates a new snapshot based on the cookie name. Any subsequent snapshot requests with the same epochhint value will be backed off the existing snapshot:

xe vdi-snapshot uuid=<valid_vdi_uuid> driver-params:epochhint=<cookie>

During NetApp SR provisioning, additional disk space is reserved for snapshots. If you plan to not use the snapshotting functionality, you might want to free up this reserved space. To do so, you can reduce the value of the other-config:multiplier parameter. By default the value of the multiplier is 2.4, so the amount of space reserved is 2.4 times the amount of space that would be needed for the FlexVols themselves.

3.3.7. Software iSCSI Support

XenServer provides support for shared SRs on iSCSI LUNs. iSCSI is supported using the open-iSCSI software iSCSI initiator or by using a supported iSCSI Host Bus Adapter (HBA). The steps for using iSCSI HBAs are identical to those for Fibre Channel HBAs, both of which are described in Section 3.3.9.2, “Creating a shared LVM over Fibre Channel / iSCSI HBA or SAS SR (lvmohba)”.

Shared iSCSI support using the software iSCSI initiator is implemented based on the Linux Volume Manager (LVM) and provides the same performance benefits provided by LVM VDIs in the local disk case. Shared iSCSI SRs using the software-based host initiator are capable of supporting VM agility using XenMotion: VMs can be started on any XenServer host in a resource pool and migrated between them with no noticeable downtime.

iSCSI SRs use the entire LUN specified at creation time and may not span more than one LUN. CHAP support is provided for client authentication, during both the data path initialization and the LUN discovery phases.

3.3.7.1. XenServer Host iSCSI configuration

All iSCSI initiators and targets must have a unique name to ensure they can be uniquely identified on the network. An initiator has an iSCSI initiator address, and a target has an iSCSI target address. Collectively these are called iSCSI Qualified Names, or IQNs.

XenServer hosts support a single iSCSI initiator which is automatically created and configured with a random IQN during host installation. The single initiator can be used to connect to multiple iSCSI targets concurrently.

iSCSI targets commonly provide access control using iSCSI initiator IQN lists, so all iSCSI targets/LUNs to be accessed by a XenServer host must be configured to allow access by the host's initiator IQN. Similarly, targets/LUNs to be used as shared iSCSI SRs must be configured to allow access by all host IQNs in the resource pool.

Note

iSCSI targets that do not provide access control will typically default to restricting LUN access to a single initiator to ensure data integrity. If an iSCSI LUN is intended for use as a shared SR across multiple XenServer hosts in a resource pool, ensure that multi-initiator access is enabled for the specified LUN.

The XenServer host IQN value can be adjusted using XenCenter, or using the CLI with the following command when using the iSCSI software initiator:

xe host-param-set uuid=<valid_host_id> other-config:iscsi_iqn=<new_initiator_iqn>

Warning

It is imperative that every iSCSI target and initiator have a unique IQN. If a non-unique IQN identifier is used, data corruption and/or denial of LUN access can occur.

Warning

Do not change the XenServer host IQN with iSCSI SRs attached. Doing so can result in failures connecting to new targets or existing SRs.

3.3.8. Managing Hardware Host Bus Adapters (HBAs)

This section covers various operations required to manage SAS, Fibre Channel and iSCSI HBAs.

3.3.8.1. Sample QLogic iSCSI HBA setup

For full details on configuring QLogic Fibre Channel and iSCSI HBAs please refer to the QLogic website.

Once the HBA is physically installed into the XenServer host, use the following steps to configure the HBA:

Set the IP networking configuration for the HBA. This example assumes DHCP and HBA port 0. Specify the appropriate values if using static IP addressing or a multi-port HBA.
```
/opt/QLogic_Corporation/SANsurferiCLI/iscli -ipdhcp 0
```

Add a persistent iSCSI target to port 0 of the HBA.

/opt/QLogic_Corporation/SANsurferiCLI/iscli -pa 0 <iscsi_target_ip_address>

Use the xe sr-probe command to force a rescan of the HBA controller and display available LUNs. See Section 3.2.5, “Probing an SR” and Section 3.3.9.2, “Creating a shared LVM over Fibre Channel / iSCSI HBA or SAS SR (lvmohba)” for more details.

3.3.8.2. Removing HBA-based SAS, FC or iSCSI device entries

Note

This step is not required. Citrix recommends that only power users perform this process if it is necessary.

Each HBA-based LUN has a corresponding global device path entry under /dev/disk/by-scsibus in the format <SCSIid>-<adapter>:<bus>:<target>:<lun> and a standard device path under /dev. To remove the device entries for LUNs no longer in use as SRs use the following steps:

Use sr-forget or sr-destroy as appropriate to remove the SR from the XenServer host database. See Section 3.4.1, “Destroying or forgetting a SR” for details.
Remove the zoning configuration within the SAN for the desired LUN to the desired host.
Use the sr-probe command to determine the ADAPTER, BUS, TARGET, and LUN values corresponding to the LUN to be removed. See Section 3.2.5, “Probing an SR” for details.

Remove the device entries with the following command:

echo "1" > /sys/class/scsi_device/<adapter>:<bus>:<target>:<lun>/device/delete

Warning

Make absolutely sure you are certain which LUN you are removing. Accidentally removing a LUN required for host operation, such as the boot or root device, will render the host unusable.

3.3.9. LVM over iSCSI

The LVM over iSCSI type represents disks as Logical Volumes within a Volume Group created on an iSCSI LUN.

3.3.9.1. Creating a shared LVM over iSCSI SR using the software iSCSI initiator (lvmoiscsi)

Device-config parameters for lvmoiscsi SRs:

Parameter Name	Description	Optional?
target	the IP address or hostname of the iSCSI filer that hosts the SR	yes
targetIQN	the IQN target address of iSCSI filer that hosts the SR	yes
SCSIid	the SCSI bus ID of the destination LUN	yes
chapuser	the username to be used for CHAP authentication	no
chappassword	the password to be used for CHAP authentication	no
port	the network port number on which to query the target	no
usediscoverynumber	the specific iscsi record index to use	no

To create a shared lvmoiscsi SR on a specific LUN of an iSCSI target use the following command.

xe sr-create host-uuid=<valid_uuid> content-type=user \
name-label=<"Example shared LVM over iSCSI SR"> shared=true \
device-config:target=<target_ip=> device-config:targetIQN=<target_iqn=> \
device-config:SCSIid=<scsci_id> \
type=lvmoiscsi

3.3.9.2. Creating a shared LVM over Fibre Channel / iSCSI HBA or SAS SR (lvmohba)

SRs of type lvmohba can be created and managed using the xe CLI or XenCenter.

Device-config parameters for lvmohba SRs:

Parameter name	Description	Required?
SCSIid	Device SCSI ID	Yes

To create a shared lvmohba SR, perform the following steps on each host in the pool:

Zone in one or more LUNs to each XenServer host in the pool. This process is highly specific to the SAN equipment in use. Please refer to your SAN documentation for details.
If necessary, use the HBA CLI included in the XenServer host to configure the HBA:
- Emulex: /usr/sbin/hbanyware
- QLogic FC: /opt/QLogic_Corporation/SANsurferCLI
- QLogic iSCSI: /opt/QLogic_Corporation/SANsurferiCLI
See
Section 3.3.8, “Managing Hardware Host Bus Adapters (HBAs)” for an example of QLogic iSCSI HBA configuration. For more information on Fibre Channel and iSCSI HBAs please refer to the Emulex and QLogic websites.

Use the sr-probe command to determine the global device path of the HBA LUN. sr-probe forces a re-scan of HBAs installed in the system to detect any new LUNs that have been zoned to the host and returns a list of properties for each LUN found. Specify the host-uuid parameter to ensure the probe occurs on the desired host. The global device path returned as the <path> property will be common across all hosts in the pool and therefore must be used as the value for the device-config:device parameter when creating the SR. If multiple LUNs are present use the vendor, LUN size, LUN serial number, or the SCSI ID as included in the <path> property to identify the desired LUN.

xe sr-probe type=lvmohba \
host-uuid=1212c7b3-f333-4a8d-a6fb-80c5b79b5b31
Error code: SR_BACKEND_FAILURE_90
Error parameters: , The request is missing the device parameter, \
<?xml version="1.0" ?>
<Devlist>
    <BlockDevice>
        <path>
            /dev/disk/by-id/scsi-360a9800068666949673446387665336f
        </path>
        <vendor>
            HITACHI
        </vendor>
        <serial>
            730157980002
        </serial>
        <size>
            80530636800
        </size>
        <adapter>
            4
        </adapter>
        <channel>
            0
        </channel>
        <id>
            4
        </id>
        <lun>
            2
        </lun>
        <hba>
            qla2xxx
        </hba>
    </BlockDevice>
    <Adapter>
        <host>
            Host4
        </host>
        <name>
            qla2xxx
        </name>
        <manufacturer>
            QLogic HBA Driver
        </manufacturer>
        <id>
            4
        </id>
    </Adapter>
</Devlist>

On the master host of the pool create the SR, specifying the global device path returned in the <path> property from sr-probe. PBDs will be created and plugged for each host in the pool automatically.

xe sr-create host-uuid=<valid_uuid> \
content-type=user \
name-label=<"Example shared LVM over HBA SR"> shared=true \
device-config:SCSIid=<device_scsi_id> type=lvmohba

Note

You can use the BRAND_CONSOLE; Repair Storage Repository function to retry the PBD creation and plugging portions of the sr-create operation. This can be valuable in cases where the LUN zoning was incorrect for one or more hosts in a pool when the SR was created. Correct the zoning for the affected hosts and use the Repair Storage Repository function instead of removing and re-creating the SR.

3.3.10. NFS VHD

The NFS VHD type stores disks as VHD files on a remote NFS filesystem.

NFS is a ubiquitous form of storage infrastructure that is available in many environments. XenServer allows existing NFS servers that support NFS V3 over TCP/IP to be used immediately as a storage repository for virtual disks (VDIs). VDIs are stored in the Microsoft VHD format only. Moreover, as NFS SRs can be shared, VDIs stored in a shared SR allow VMs to be started on any XenServer hosts in a resource pool and be migrated between them using XenMotion with no noticeable downtime.

Creating an NFS SR requires the hostname or IP address of the NFS server. The sr-probe command provides a list of valid destination paths exported by the server on which the SR can be created. The NFS server must be configured to export the specified path to all XenServer hosts in the pool, or the creation of the SR and the plugging of the PBD record will fail.

As mentioned at the beginning of this chapter, VDIs stored on NFS are sparse. The image file is allocated as the VM writes data into the disk. This has the considerable benefit that VM image files take up only as much space on the NFS storage as is required. If a 100GB VDI is allocated for a new VM and an OS is installed, the VDI file will only reflect the size of the OS data that has been written to the disk rather than the entire 100GB.

VHD files may also be chained, allowing two VDIs to share common data. In cases where a NFS-based VM is cloned, the resulting VMs will share the common on-disk data at the time of cloning. Each will proceed to make its own changes in an isolated copy-on-write version of the VDI. This feature allows NFS-based VMs to be quickly cloned from templates, facilitating very fast provisioning and deployment of new VMs.

Note

The maximum supported length of VHD chains is 30.

As VHD-based images require extra metadata to support sparseness and chaining, the format is not as high-performance as LVM-based storage. In cases where performance really matters, it is well worth forcibly allocating the sparse regions of an image file. This will improve performance at the cost of consuming additional disk space.

XenServer's NFS and VHD implementations assume that they have full control over the SR directory on the NFS server. Administrators should not modify the contents of the SR directory, as this can risk corrupting the contents of VDIs.

XenServer has been tuned for enterprise-class storage that use non-volatile RAM to provide fast acknowledgments of write requests while maintaining a high degree of data protection from failure. XenServer has been tested extensively against Network Appliance FAS270c and FAS3020c storage, using Data OnTap 7.2.2.

In situations where XenServer is used with lower-end storage, it will cautiously wait for all writes to be acknowledged before passing acknowledgments on to guest VMs. This will incur a noticeable performance cost, and might be remedied by setting the storage to present the SR mount point as an asynchronous mode export. Asynchronous exports acknowledge writes that are not actually on disk, and so administrators should consider the risks of failure carefully in these situations.

The XenServer NFS implementation uses TCP by default. If your situation allows, you can configure the implementation to use UDP in situations where there may be a performance benefit. To do this, specify the device-config parameter useUDP=true at SR creation time.

Warning

Since VDIs on NFS SRs are created as sparse, administrators must ensure that there is enough disk space on the NFS SRs for all required VDIs. XenServer hosts do not enforce that the space required for VDIs on NFS SRs is actually present.

3.3.10.1. Creating a shared NFS SR (nfs)

Device-config parameters for nfs SRs:

Parameter Name	Description	Required?
server	IP address or hostname of the NFS server	Yes
serverpath	path, including the NFS mount point, to the NFS server that hosts the SR	Yes

To create a shared NFS SR on 192.168.1.10:/export1 use the following command.

xe sr-create host-uuid=<host_uuid> content-type=user \
name-label=<"Example shared NFS SR"> shared=true \
device-config:server=<192.168.1.10> device-config:serverpath=</export1> type=nfs

3.3.11. LVM over hardware HBA

The LVM over hardware HBA type represents disks as VHDs on Logical Volumes within a Volume Group created on an HBA LUN providing, for example, hardware-based iSCSI or FC support.

XenServer hosts support Fibre Channel (FC) storage area networks (SANs) through Emulex or QLogic host bus adapters (HBAs). All FC configuration required to expose a FC LUN to the host must be completed manually, including storage devices, network devices, and the HBA within the XenServer host. Once all FC configuration is complete the HBA will expose a SCSI device backed by the FC LUN to the host. The SCSI device can then be used to access the FC LUN as if it were a locally attached SCSI device.

Use the sr-probe command to list the LUN-backed SCSI devices present on the host. This command forces a scan for new LUN-backed SCSI devices. The path value returned by sr-probe for a LUN-backed SCSI device is consistent across all hosts with access to the LUN, and therefore must be used when creating shared SRs accessible by all hosts in a resource pool.

The same features apply to QLogic iSCSI HBAs.

See Section 3.2.1, “Creating Storage Repositories” for details on creating shared HBA-based FC and iSCSI SRs.

Note

XenServer support for Fibre Channel does not support direct mapping of a LUN to a VM. HBA-based LUNs must be mapped to the host and specified for use in an SR. VDIs within the SR are exposed to VMs as standard block devices.

3.3.12. Citrix StorageLink Gateway (CSLG) SRs

The CSLG storage repository allows use of the Citrix StorageLink service for native access to a range of iSCSI and Fibre Channel arrays and automated fabric/initiator and array configuration features. Installation and configuration of the StorageLink service is required, for more information please see the StorageLink documentation.

Note

Running the StorageLink service in a VM within a resource pool to which the StorageLink service is providing storage is not supported in combination with the XenServer High Availability (HA) features. To use CSLG SRs in combination with HA ensure the StorageLink service is running outside the HA-enabled pool.

CSLG SRs can be created using the xe CLI only. After creation CSLG SRs can be viewed and managed using both the xe CLI and XenCenter.

Because the CSLG SR can be used to access different storage arrays, the exact features available for a given CSLG SR depend on the capabilities of the array. All CSLG SRs use a LUN-per-VDI model where a new LUN is provisioned for each virtual disk. (VDI).

CSLG SRs can co-exist with other SR types on the same storage array hardware, and multiple CSLG SRs can be defined within the same resource pool.

The StorageLink service can be configured using the StorageLink Manager or from within the XenServer control domain using the StorageLink Command Line Interface (CLI). To run the StorageLink (CLI) use the following command, where <hostname> is the name or IP address of the machine running the StorageLink service:

/opt/Citrix/StorageLink/bin/csl \
server=<hostname>[:<port>][,<username>,<password>]

For more information about the StorageLink CLI please see the StorageLink documentation or use the /opt/Citrix/StorageLink/bin/csl help command.

3.3.12.1. Creating a shared StorageLink SR

SRs of type CSLG can only be created by using the xe Command Line Interface (CLI). Once created CSLG SRs can be managed using either XenCenter or the xe CLI.

The device-config parameters for CSLG SRs are:

Parameter name	Description	Optional?
target	The server name or IP address of the machine running the StorageLink service	No
storageSystemId	The storage system ID to use for allocating storage	No
storagePoolId	The storage pool ID within the specified storage system to use for allocating storage	No
username	The username to use for connection to the StorageLink service	Yes ^[a]
password	The password to use for connecting to the StorageLink service	Yes ^[a]
cslport	The port to use for connecting to the StorageLink service	Yes ^[a]
chapuser	The username to use for CHAP authentication	Yes
chappassword	The password to use for CHAP authentication	Yes
protocol	Specifies the storage protocol to use (fc or iscsi) for multi-protocol storage systems. If not specified fc is used if available, otherwise iscsi.	Yes
provision-type	Specifies whether to use thick or thin provisioning (thick or thin); default is thick	Yes
provision-options	Additional provisioning options: Set to `dedup` to use the de-duplication features supported by the storage system	Yes
raid-type	The level of RAID to use for the SR, as supported by the storage array	Yes
^[a]If the username, password, or port configuration of the StorageLink service are changed from the default then the appropriate parameter and value must be specified.

SRs of type cslg support two additional parameters that can be used with storage arrays that support LUN grouping features, such as NetApp flexvols.

sm-config parameters for CSLG SRs:

Parameter name	Description	Optional?
pool-count	Creates the specified number of groups on the array, in which LUNs provisioned within the SR will be created	Yes
physical-size	The total size of the SR in MB. Each pool will be created with a size equal to physical-size divided by pool-count.	Yes ^[a]
^[a]Required when specifying the `sm-config:pool-count parameter`

Note

When a new NetApp SR is created using StorageLink, by default a single FlexVol is created for the SR that contains all LUNs created for the SR. To change this behaviour and specify the number of FlexVols to create and the size of each FlexVol, use the sm-config:pool-size and sm-config:physical-size parameters. sm-config:pool-size specifies the number of FlexVols. sm-config:physical-size specifies the total size of all FlexVols to be created, so that each FlexVol will be of size sm-config:physical-size divided by sm-config:pool-size.

To create a CSLG SR

Install the StorageLink service onto a Windows host or virtual machine
Configure the StorageLink service with the appropriate storage adapters and credentials

Use the sr-probe command with the device-config:target parameter to identify the available storage system IDs

xe sr-probe type=cslg device-config:target=192.168.128.10

<csl__storageSystemInfoList>
    <csl__storageSystemInfo>
        <friendlyName>5001-4380-013C-0240</friendlyName>
        <displayName>HP EVA (5001-4380-013C-0240)</displayName>
        <vendor>HP</vendor>
        <model>EVA</model>
        <serialNum>50014380013C0240</serialNum>
        <storageSystemId>HP__EVA__50014380013C0240</storageSystemId>
        <systemCapabilities>
            <capabilities>PROVISIONING</capabilities>
            <capabilities>MAPPING</capabilities>
            <capabilities>MULTIPLE_STORAGE_POOLS</capabilities>
            <capabilities>DIFF_SNAPSHOT</capabilities>
            <capabilities>CLONE</capabilities>
        </systemCapabilities>
        <protocolSupport>
            <capabilities>FC</capabilities>
        </protocolSupport>
        <csl__snapshotMethodInfoList>
            <csl__snapshotMethodInfo>
                <name>5001-4380-013C-0240</name>
                <displayName></displayName>
                <maxSnapshots>16</maxSnapshots>
                <supportedNodeTypes>
                    <nodeType>STORAGE_VOLUME</nodeType>
                </supportedNodeTypes>
                <snapshotTypeList>
                </snapshotTypeList>
                <snapshotCapabilities>
                </snapshotCapabilities>
            </csl__snapshotMethodInfo>
            <csl__snapshotMethodInfo>
                <name>5001-4380-013C-0240</name>
                <displayName></displayName>
                <maxSnapshots>16</maxSnapshots>
                <supportedNodeTypes>
                    <nodeType>STORAGE_VOLUME</nodeType>
                </supportedNodeTypes>
                <snapshotTypeList>
                    <snapshotType>DIFF_SNAPSHOT</snapshotType>
                </snapshotTypeList>
                <snapshotCapabilities>
                </snapshotCapabilities>
            </csl__snapshotMethodInfo>
            <csl__snapshotMethodInfo>
                <name>5001-4380-013C-0240</name>
                <displayName></displayName>
                <maxSnapshots>16</maxSnapshots>
                <supportedNodeTypes>
                    <nodeType>STORAGE_VOLUME</nodeType>
                </supportedNodeTypes>
                <snapshotTypeList>
                    <snapshotType>CLONE</snapshotType>
                </snapshotTypeList>
               <snapshotCapabilities>
               </snapshotCapabilities>
            </csl__snapshotMethodInfo>
        </csl__snapshotMethodInfoList>
    </csl__storageSystemInfo>
</csl__storageSystemInfoList>

You can use grep to filter the sr-probe output to just the storage pool IDs

xe sr-probe type=cslg device-config:target=192.168.128.10 | grep storageSystemId
        <storageSystemId>EMC__CLARIION__APM00074902515</storageSystemId>
        <storageSystemId>HP__EVA__50014380013C0240</storageSystemId>
        <storageSystemId>NETAPP__LUN__0AD4F00A</storageSystemId>

Add the desired storage system ID to the sr-probe command to identify the storage pools available within the specified storage system

xe sr-probe type=cslg \
device-config:target=192.168.128.10  \ device-config:storageSystemId=HP__EVA__50014380013C0240
<?xml version="1.0" encoding="iso-8859-1"?>
<csl__storagePoolInfoList>
    <csl__storagePoolInfo>
        <displayName>Default Disk Group</displayName>
        <friendlyName>Default Disk Group</friendlyName>
        <storagePoolId>00010710B4080560B6AB08000080000000000400</storagePoolId>
        <parentStoragePoolId></parentStoragePoolId>
        <storageSystemId>HP__EVA__50014380013C0240</storageSystemId>
        <sizeInMB>1957099</sizeInMB>
        <freeSpaceInMB>1273067</freeSpaceInMB>
        <isDefault>No</isDefault>
        <status>0</status>
        <provisioningOptions>
            <supportedRaidTypes>
                <raidType>RAID0</raidType>
                <raidType>RAID1</raidType>
                <raidType>RAID5</raidType>
            </supportedRaidTypes>
            <supportedNodeTypes>
                <nodeType>STORAGE_VOLUME</nodeType>
            </supportedNodeTypes>
        <supportedProvisioningTypes>
        </supportedProvisioningTypes>
        </provisioningOptions>
    </csl__storagePoolInfo>
</csl__storagePoolInfoList>

You can use grep to filter the sr-probe output to just the storage pool IDs

xe sr-probe type=cslg \
device-config:target=192.168.128.10 \
device-config:storageSystemId=HP__EVA__50014380013C0240 \
| grep storagePoolId
<storagePoolId>00010710B4080560B6AB08000080000000000400</storagePoolId>

Create the SR specifying the desired storage system and storage pool IDs

xe sr-create type=cslg name-label=CSLG_EVA_1 shared=true \
device-config:target=192.168.128.10 \
device-config:storageSystemId=HP__EVA__50014380013C0240 \
device-config:storagePoolId=00010710B4080560B6AB08000080000000000400

3.4. Managing Storage Repositories

This section covers various operations required in the ongoing management of Storage Repositories (SRs).

3.4.1. Destroying or forgetting a SR

You can destroy an SR, which actually deletes the contents of the SR from the physical media. Alternatively you can forget an SR, which allows you to re-attach the SR, for example, to another XenServer host, without removing any of the SR contents. In both cases, the PBD of the SR must first be unplugged. Forgetting an SR is the equivalent of the SR Detach operation within XenCenter.

Unplug the PBD to detach the SR from the corresponding XenServer host:
```
xe pbd-unplug uuid=<pbd_uuid>
```
To destroy the SR, which deletes both the SR and corresponding PBD from the XenServer host database and deletes the SR contents from the physical media:
```
xe sr-destroy uuid=<sr_uuid>
```
Or, to forget the SR, which removes the SR and corresponding PBD from the XenServer host database but leaves the actual SR contents intact on the physical media:
```
xe sr-forget uuid=<sr_uuid>
```

Note

It might take some time for the software object corresponding to the SR to be garbage collected.

3.4.2. Introducing an SR

Introducing an SR that has been forgotten requires introducing an SR, creating a PBD, and manually plugging the PBD to the appropriate XenServer hosts to activate the SR.

The following example introduces a SR of type lvmoiscsi.

Probe the existing SR to determine its UUID:

xe sr-probe type=lvmoiscsi device-config:target=<192.168.1.10> \ 
device-config:targetIQN=<192.168.1.10:filer1> \
device-config:SCSIid=<149455400000000000000000002000000b70200000f000000>

Introduce the existing SR UUID returned from the sr-probe command. The UUID of the new SR is returned:

xe sr-introduce content-type=user name-label=<"Example Shared LVM over iSCSI SR">
shared=true uuid=<valid_sr_uuid> type=lvmoiscsi

Create a PBD to accompany the SR. The UUID of the new PBD is returned:

xe pbd-create type=lvmoiscsi host-uuid=<valid_uuid> sr-uuid=<valid_sr_uuid> \
device-config:target=<192.168.0.1> \
device-config:targetIQN=<192.168.1.10:filer1> \
device-config:SCSIid=<149455400000000000000000002000000b70200000f000000>

Plug the PBD to attach the SR:
```
xe pbd-plug uuid=<pbd_uuid>
```
Verify the status of the PBD plug. If successful the currently-attached property will be true:
```
xe pbd-list sr-uuid=<sr_uuid>
```

Note

Steps 3 through 5 must be performed for each host in the resource pool, and can also be performed using the Repair Storage Repository function in XenCenter.

3.4.3. Resizing an SR

If you have resized the LUN on which a iSCSI or HBA SR is based, use the following procedures to reflect the size change in XenServer:

iSCSI SRs - unplug all PBDs on the host that reference LUNs on the same target. This is required to reset the iSCSI connection to the target, which in turn will allow the change in LUN size to be recognized when the PBDs are replugged.
HBA SRs - reboot the host.

Note

In previous versions of XenServer explicit commands were required to resize the physical volume group of iSCSI and HBA SRs. These commands are now issued as part of the PBD plug operation and are no longer required.

3.4.4. Converting local Fibre Channel SRs to shared SRs

Use the xe CLI and the XenCenter Repair Storage Repository feature to convert a local FC SR to a shared FC SR:

Upgrade all hosts in the resource pool to XenServer 5.5.0.
Ensure all hosts in the pool have the SR's LUN zoned appropriately. See Section 3.2.5, “Probing an SR” for details on using the sr-probe command to verify the LUN is present on each host.

Convert the SR to shared:

xe sr-param-set shared=true uuid=<local_fc_sr>

Within XenCenter the SR is moved from the host level to the pool level, indicating that it is now shared. The SR will be marked with a red exclamation mark to show that it is not currently plugged on all hosts in the pool.
Select the SR and then select the Storage > Repair Storage Repository menu option.
Click Repair to create and plug a PBD for each host in the pool.

3.4.5. Moving Virtual Disk Images (VDIs) between SRs

The set of VDIs associated with a VM can be copied from one SR to another to accommodate maintenance requirements or tiered storage configurations. XenCenter provides the ability to copy a VM and all of its VDIs to the same or a different SR, and a combination of XenCenter and the xe CLI can be used to copy individual VDIs.

3.4.5.1. Copying all of a VM's VDIs to a different SR

The XenCenter Copy VM function creates copies of all VDIs for a selected VM on the same or a different SR. The source VM and VDIs are not affected by default. To move the VM to the selected SR rather than creating a copy, select the Remove original VM option in the Copy Virtual Machine dialog box.

Shutdown the VM.
Within XenCenter select the VM and then select the VM > Copy VM menu option.
Select the desired target SR.

3.4.5.2. Copying individual VDIs to a different SR

A combination of the xe CLI and XenCenter can be used to copy individual VDIs between SRs.

Shutdown the VM.
Use the xe CLI to identify the UUIDs of the VDIs to be moved. If the VM has a DVD drive its vdi-uuid will be listed as <not in database> and can be ignored.
```
xe vbd-list vm-uuid=<valid_vm_uuid>
```
Note
The vbd-list command displays both the VBD and VDI UUIDs. Be sure to record the VDI UUIDs rather than the VBD UUIDs.
In XenCenter select the VM's Storage tab. For each VDI to be moved, select the VDI and click the Detach button. This step can also be done using the vbd-destroy command.
Note
If you use the vbd-destroy command to detach the VDI UUIDs, be sure to first check if the VBD has the parameter other-config:owner set to true. If so, set it to false. Issuing the vbd-destroy command with other-config:owner=true will also destroy the associated VDI.
Use the vdi-copy command to copy each of the VM's VDIs to be moved to the desired SR.
```
xe vdi-copy uuid=<valid_vdi_uuid> sr-uuid=<valid_sr_uuid>
```
Within XenCenter select the VM's Storage tab. Click the Attach button and select the VDIs from the new SR. This step can also be done use the vbd-create command.
To delete the original VDIs, within XenCenter select the Storage tab of the original SR. The original VDIs will be listed with an empty value for the VM field and can be deleted with the Delete button.

3.4.6. Adjusting the disk IO scheduler

For general performance, the default disk scheduler noop is applied on all new SR types. The noop scheduler provides the fairest performance for competing VMs accessing the same device. To apply disk QoS (see Section 3.5, “Virtual disk QoS settings”) it is necessary to override the default setting and assign the cfq disk scheduler to the SR. The corresponding PBD must be unplugged and re-plugged for the scheduler parameter to take effect. The disk scheduler can be adjusted using the following command:

xe sr-param-set other-config:scheduler=noop|cfq|anticipatory|deadline \
uuid=<valid_sr_uuid>

Note

This will not effect EqualLogic, NetApp or NFS storage.

3.5. Virtual disk QoS settings

Virtual disks have an optional I/O priority Quality of Service (QoS) setting. This setting can be applied to existing virtual disks using the xe CLI as described in this section.

In the shared SR case, where multiple hosts are accessing the same LUN, the QoS setting is applied to VBDs accessing the LUN from the same host. QoS is not applied across hosts in the pool.

Before configuring any QoS parameters for a VBD, ensure that the disk scheduler for the SR has been set appropriately. See Section 3.4.6, “Adjusting the disk IO scheduler” for details on how to adjust the scheduler. The scheduler parameter must be set to cfq on the SR for which the QoS is desired.

Note

Remember to set the scheduler to cfq on the SR, and to ensure that the PBD has been re-plugged in order for the scheduler change to take effect.

The first parameter is qos_algorithm_type. This parameter needs to be set to the value ionice, which is the only type of QoS algorithm supported for virtual disks in this release.

The QoS parameters themselves are set with key/value pairs assigned to the qos_algorithm_param parameter. For virtual disks, qos_algorithm_param takes a sched key, and depending on the value, also requires a class key.

Possible values of qos_algorithm_param:sched are:

sched=rt or sched=real-time sets the QoS scheduling parameter to real time priority, which requires a class parameter to set a value
sched=idle sets the QoS scheduling parameter to idle priority, which requires no class parameter to set any value
sched=<anything> sets the QoS scheduling parameter to best effort priority, which requires a class parameter to set a value

The possible values for class are:

One of the following keywords: highest, high, normal, low, lowest
an integer between 0 and 7, where 7 is the highest priority and 0 is the lowest, so that, for example, I/O requests with a priority of 5, will be given priority over I/O requests with a priority of 2.

To enable the disk QoS settings, you also need to set the other-config:scheduler to cfq and replug PBDs for the storage in question.

For example, the following CLI commands set the virtual disk's VBD to use real time priority 5:

xe vbd-param-set uuid=<vbd_uuid> qos_algorithm_type=ionice
xe vbd-param-set uuid=<vbd_uuid> qos_algorithm_params:sched=rt
xe vbd-param-set uuid=<vbd_uuid> qos_algorithm_params:class=5
xe sr-param-set uuid=<sr_uuid> other-config:scheduler-cfq
xe pbd-plug uuid=<pbd_uuid>

Chapter 4. Networking

This chapter discusses how physical network interface cards (NICs) in XenServer hosts are used to enable networking within Virtual Machines (VMs). XenServer supports up to 6 physical network interfaces (or up to 6 pairs of bonded network interfaces) per XenServer host and up to 7 virtual network interfaces per VM.

Note

XenServer provides automated configuration and management of NICs using the xe command line interface (CLI). Unlike previous XenServer versions, the host networking configuration files should not be edited directly in most cases; where a CLI command is available, do not edit the underlying files.

If you are already familiar with XenServer networking concepts, you may want to skip ahead to one of the following sections:

For procedures on how to create networks for standalone XenServer hosts, see Section 4.2.1, “Creating networks in a standalone server”.
For procedures on how to create networks for XenServer hosts that are configured in a resource pool, see Section 4.2.2, “Creating networks in resource pools”.
For procedures on how to create VLANs for XenServer hosts, either standalone or part of a resource pool, see Section 4.2.3, “Creating VLANs”.
For procedures on how to create bonds for standalone XenServer hosts, see Section 4.2.4, “Creating NIC bonds on a standalone host”.
For procedures on how to create bonds for XenServer hosts that are configured in a resource pool, see Section 4.2.5, “Creating NIC bonds in resource pools”.

4.1. XenServer networking overview

This section describes the general concepts of networking in the XenServer environment.

Note

Some networking options have different behaviors when used with standalone XenServer hosts compared to resource pools. This chapter contains sections on general information that applies to both standalone hosts and pools, followed by specific information and procedures for each.

4.1.1. Network objects

There are three types of server-side software objects which represent networking entities. These objects are:

A PIF, which represents a physical network interface on a XenServer host. PIF objects have a name and description, a globally unique UUID, the parameters of the NIC that they represent, and the network and server they are connected to.
A VIF, which represents a virtual interface on a Virtual Machine. VIF objects have a name and description, a globally unique UUID, and the network and VM they are connected to.
A network, which is a virtual Ethernet switch on a XenServer host. Network objects have a name and description, a globally unique UUID, and the collection of VIFs and PIFs connected to them.

Both XenCenter and the xe CLI allow configuration of networking options, control over which NIC is used for management operations, and creation of advanced networking features such as virtual local area networks (VLANs) and NIC bonds.

From XenCenter much of the complexity of XenServer networking is hidden. There is no mention of PIFs for XenServer hosts nor VIFs for VMs.

4.1.2. Networks

Each XenServer host has one or more networks, which are virtual Ethernet switches. Networks without an association to a PIF are considered internal, and can be used to provide connectivity only between VMs on a given XenServer host, with no connection to the outside world. Networks with a PIF association are considered external, and provide a bridge between VIFs and the PIF connected to the network, enabling connectivity to resources available through the PIF's NIC.

4.1.3. VLANs

Virtual Local Area Networks (VLANs), as defined by the IEEE 802.1Q standard, allow a single physical network to support multiple logical networks. XenServer hosts can work with VLANs in multiple ways.

Note

All supported VLAN configurations are equally applicable to pools and standalone hosts, and bonded and non-bonded configurations.

4.1.3.1. Using VLANs with host management interfaces

Switch ports configured to perform 802.1Q VLAN tagging/untagging, commonly referred to as ports with a native VLAN or as access mode ports, can be used with XenServer management interfaces to place management traffic on a desired VLAN. In this case the XenServer host is unaware of any VLAN configuration.

XenServer management interfaces cannot be assigned to a XenServer VLAN via a trunk port.

4.1.3.2. Using VLANs with virtual machines

Switch ports configured as 802.1Q VLAN trunk ports can be used in combination with the XenServer VLAN features to connect guest virtual network interfaces (VIFs) to specific VLANs. In this case the XenServer host performs the VLAN tagging/untagging functions for the guest, which is unaware of any VLAN configuration.

XenServer VLANs are represented by additional PIF objects representing VLAN interfaces corresponding to a specified VLAN tag. XenServer networks can then be connected to the PIF representing the physical NIC to see all traffic on the NIC, or to a PIF representing a VLAN to see only the traffic with the specified VLAN tag.

For procedures on how to create VLANs for XenServer hosts, either standalone or part of a resource pool, see Section 4.2.3, “Creating VLANs”.

4.1.3.3. Using VLANs with dedicated storage NICs

Dedicated storage NICs can be configured to use native VLAN / access mode ports as described above for management interfaces, or with trunk ports and XenServer VLANs as described above for virtual machines. To configure dedicated storage NICs, see Section 4.2.6, “Configuring a dedicated storage NIC”.

4.1.3.4. Combining management interfaces and guest VLANs on a single host NIC

A single switch port can be configured with both trunk and native VLANs, allowing one host NIC to be used for a management interface (on the native VLAN) and for connecting guest VIFs to specific VLAN IDs.

4.1.4. NIC bonds

NIC bonds can improve XenServer host resiliency by using two physical NICs as if they were one. If one NIC within the bond fails the host's network traffic will automatically be routed over the second NIC. NIC bonds work in an active/active mode, with traffic balanced between the bonded NICs.

XenServer NIC bonds completely subsume the underlying physical devices (PIFs). In order to activate a bond the underlying PIFs must not be in use, either as the management interface for the host or by running VMs with VIFs attached to the networks associated with the PIFs.

XenServer NIC bonds are represented by additional PIFs. The bond PIF can then be connected to a XenServer network to allow VM traffic and host management functions to occur over the bonded NIC. The exact steps to use to create a NIC bond depend on the number of NICs in your host, and whether the management interface of the host is assigned to a PIF to be used in the bond.

XenServer supports Source Level Balancing (SLB) NIC bonding. SLB bonding:

is an active/active mode, but only supports load-balancing of VM traffic across the physical NICs
provides fail-over support for all other traffic types
does not require switch support for Etherchannel or 802.3ad (LACP)
load balances traffic between multiple interfaces at VM granularity by sending traffic through different interfaces based on the source MAC address of the packet
is derived from the open source ALB mode and reuses the ALB capability to dynamically re-balance load across interfaces

Any given VIF will only use one of the links in the bond at a time. At startup no guarantees are made about the affinity of a given VIF to a link in the bond. However, for VIFs with high throughput, periodic rebalancing ensures that the load on the links is approximately equal.

API Management traffic can be assigned to a XenServer bond interface and will be automatically load-balanced across the physical NICs.

XenServer bonded PIFs do not require IP configuration for the bond when used for guest traffic. This is because the bond operates at Layer 2 of the OSI, the data link layer, and no IP addressing is used at this layer. When used for non-guest traffic (to connect to it with XenCenter for management, or to connect to shared network storage), one IP configuration is required per bond. (Incidentally, this is true of unbonded PIFs as well, and is unchanged from XenServer 4.1.0.)

Gratuitous ARP packets are sent when assignment of traffic changes from one interface to another as a result of fail-over.

Re-balancing is provided by the existing ALB re-balance capabilities: the number of bytes going over each slave (interface) is tracked over a given period. When a packet is to be sent that contains a new source MAC address it is assigned to the slave interface with the lowest utilization. Traffic is re-balanced every 10 seconds.

Note

Bonding is set up with an Up Delay of 31000ms and a Down Delay of 200ms. The seemingly long Up Delay is purposeful because of the time taken by some switches to actually start routing traffic. Without it, when a link comes back after failing, the bond might rebalance traffic onto it before the switch is ready to pass traffic. If you want to move both connections to a different switch, move one, then wait 31 seconds for it to be used again before moving the other.

4.1.5. Initial networking configuration

The XenServer host networking configuration is specified during initial host installation. Options such as IP address configuration (DHCP/static), the NIC used as the management interface, and hostname are set based on the values provided during installation.

When a XenServer host has a single NIC, the follow configuration is present after installation:

a single PIF is created corresponding to the host's single NIC
the PIF is configured with the IP addressing options specified during installation and to enable management of the host
the PIF is set for use in host management operations
a single network, network 0, is created
network 0 is connected to the PIF to enable external connectivity to VMs

When a host has multiple NICs the configuration present after installation depends on which NIC is selected for management operations during installation:

PIFs are created for each NIC in the host
the PIF of the NIC selected for use as the management interface is configured with the IP addressing options specified during installation
a network is created for each PIF ("network 0", "network 1", etc.)
each network is connected to one PIF
the IP addressing options of all other PIFs are left unconfigured

In both cases the resulting networking configuration allows connection to the XenServer host by XenCenter, the xe CLI, and any other management software running on separate machines via the IP address of the management interface. The configuration also provides external networking for VMs created on the host.

The PIF used for management operations is the only PIF ever configured with an IP address. External networking for VMs is achieved by bridging PIFs to VIFs using the network object which acts as a virtual Ethernet switch.

The steps required for networking features such as VLANs, NIC bonds, and dedicating a NIC to storage traffic are covered in the following sections.

4.2. Managing networking configuration

Some of the network configuration procedures in this section differ depending on whether you are configuring a stand-alone server or a server that is part of a resource pool.

4.2.1. Creating networks in a standalone server

Because external networks are created for each PIF during host installation, creating additional networks is typically only required to:

use an internal network
support advanced operations such as VLANs or NIC bonding

To add or remove networks using XenCenter, refer to the XenCenter online Help.

To add a new network using the CLI

Open the XenServer host text console.
Create the network with the network-create command, which returns the UUID of the newly created network:
```
xe network-create name-label=<mynetwork>
```

At this point the network is not connected to a PIF and therefore is internal.

4.2.2. Creating networks in resource pools

All XenServer hosts in a resource pool should have the same number of physical network interface cards (NICs), although this requirement is not strictly enforced when a XenServer host is joined to a pool.

Having the same physical networking configuration for XenServer hosts within a pool is important because all hosts in a pool share a common set of XenServer networks. PIFs on the individual hosts are connected to pool-wide networks based on device name. For example, all XenServer hosts in a pool with an eth0 NIC will have a corresponding PIF plugged into the pool-wide Network 0 network. The same will be true for hosts with eth1 NICs and Network 1, as well as other NICs present in at least one XenServer host in the pool.

If one XenServer host has a different number of NICs than other hosts in the pool, complications can arise because not all pool networks will be valid for all pool hosts. For example, if hosts host1 and host2 are in the same pool and host1 has four NICs while host2 only has two, only the networks connected to PIFs corresponding to eth0 and eth1 will be valid on host2. VMs on host1 with VIFs connected to networks corresponding to eth2 and eth3 will not be able to migrate to host host2.

All NICs of all XenServer hosts within a resource pool must be configured with the same MTU size.

4.2.3. Creating VLANs

For servers in a resource pool, you can use the pool-vlan-create command. This command creates the VLAN and automatically creates and plugs in the required PIFs on the hosts in the pool. See Section 8.4.22.2, “pool-vlan-create” for more information.

To connect a network to an external VLAN using the CLI

Open the XenServer host text console.

Create a new network for use with the VLAN. The UUID of the new network is returned:

xe network-create name-label=network5

Use the pif-list command to find the UUID of the PIF corresponding to the physical NIC supporting the desired VLAN tag. The UUIDs and device names of all PIFs are returned, including any existing VLANs:

xe pif-list

Create a VLAN object specifying the desired physical PIF and VLAN tag on all VMs to be connected to the new VLAN. A new PIF will be created and plugged into the specified network. The UUID of the new PIF object is returned.

xe vlan-create network-uuid=<network_uuid> pif-uuid=<pif_uuid> vlan=5

Attach VM VIFs to the new network. See Section 4.2.1, “Creating networks in a standalone server” for more details.

4.2.4. Creating NIC bonds on a standalone host

Citrix recommends using XenCenter to create NIC bonds. For details, refer to the XenCenter help.

This section describes how to use the xe CLI to create bonded NIC interfaces on a standalone XenServer host. See Section 4.2.5, “Creating NIC bonds in resource pools” for details on using the xe CLI to create NIC bonds on XenServer hosts that comprise a resource pool.

4.2.4.1. Creating a NIC bond on a dual-NIC host

Creating a bond on a dual-NIC host implies that the PIF/NIC currently in use as the management interface for the host will be subsumed by the bond. The additional steps required to move the management interface to the bond PIF are included.

Bonding two NICs together

Use XenCenter or the vm-shutdown command to shut down all VMs on the host, thereby forcing all VIFs to be unplugged from their current networks. The existing VIFs will be invalid after the bond is enabled.

xe vm-shutdown uuid=<vm_uuid>

Use the network-create command to create a new network for use with the bonded NIC. The UUID of the new network is returned:

xe network-create name-label=<bond0>

Use the pif-list command to determine the UUIDs of the PIFs to use in the bond:

xe pif-list

Use the bond-create command to create the bond by specifying the newly created network UUID and the UUIDs of the PIFs to be bonded separated by commas. The UUID for the bond is returned:
```
xe bond-create network-uuid=<network_uuid> pif-uuids=<pif_uuid_1>,<pif_uuid_2>
```
Note
See Section 4.2.4.2, “Controlling the MAC address of the bond” for details on controlling the MAC address used for the bond PIF.
Use the pif-list command to determine the UUID of the new bond PIF:
```
xe pif-list device=<bond0>
```
Use the pif-reconfigure-ip command to configure the desired management interface IP address settings for the bond PIF. See Chapter 8, Command line interface for more detail on the options available for the pif-reconfigure-ip command.
```
xe pif-reconfigure-ip uuid=<bond_pif_uuid> mode=DHCP
```
Use the host-management-reconfigure command to move the management interface from the existing physical PIF to the bond PIF. This step will activate the bond:
```
xe host-management-reconfigure pif-uuid=<bond_pif_uuid>
```
Use the pif-reconfigure-ip command to remove the IP address configuration from the non-bonded PIF previously used for the management interface. This step is not strictly necessary but might help reduce confusion when reviewing the host networking configuration.
```
xe pif-reconfigure-ip uuid=<old_management_pif_uuid> mode=None
```
Move existing VMs to the bond network using the vif-destroy and vif-create commands. This step can also be completed using XenCenter by editing the VM configuration and connecting the existing VIFs of a VM to the bond network.
Restart the VMs shut down in step 1.

4.2.4.2. Controlling the MAC address of the bond

Creating a bond on a dual-NIC host implies that the PIF/NIC currently in use as the management interface for the host will be subsumed by the bond. If DHCP is used to supply IP addresses to the host in most cases the MAC address of the bond should be the same as the PIF/NIC currently in use, allowing the IP address of the host received from DHCP to remain unchanged.

The MAC address of the bond can be changed from PIF/NIC currently in use for the management interface, but doing so will cause existing network sessions to the host to be dropped when the bond is enabled and the MAC/IP address in use changes.

The MAC address to be used for a bond can be controlled in two ways:

an optional mac parameter can be specified in the bond-create command. Using this parameter, the bond MAC address can be set to any arbitrary address.
If the mac parameter is not specified, the MAC address of the first PIF listed in the pif-uuids parameter is used for the bond.

4.2.4.3. Reverting NIC bonds

If reverting a XenServer host to a non-bonded configuration, be aware of the following requirements:

As when creating a bond, all VMs with VIFs on the bond must be shut down prior to destroying the bond. After reverting to a non-bonded configuration, reconnect the VIFs to an appropriate network.
Move the management interface to another PIF using the pif-reconfigure-ip and host-management-reconfigure commands prior to issuing the bond-destroy command, otherwise connections to the host (including XenCenter) will be dropped.

4.2.5. Creating NIC bonds in resource pools

Whenever possible, create NIC bonds as part of initial resource pool creation prior to joining additional hosts to the pool or creating VMs. Doing so allows the bond configuration to be automatically replicated to hosts as they are joined to the pool and reduces the number of steps required. Adding a NIC bond to an existing pool requires creating the bond configuration manually on the master and each of the members of the pool. Adding a NIC bond to an existing pool after VMs have been installed is also a disruptive operation, as all VMs in the pool must be shut down.

Citrix recommends using XenCenter to create NIC bonds. For details, refer to the XenCenter help.

This section describes using the xe CLI to create bonded NIC interfaces on XenServer hosts that comprise a resource pool. See Section 4.2.4.1, “Creating a NIC bond on a dual-NIC host” for details on using the xe CLI to create NIC bonds on a standalone XenServer host.

Warning

Do not attempt to create network bonds while HA is enabled. The process of bond creation will disturb the in-progress HA heartbeating and cause hosts to self-fence (shut themselves down); subsequently they will likely fail to reboot properly and will need the host-emergency-ha-disable command to recover.

4.2.5.1. Adding NIC bonds to new resource pools

Select the host you want to be the master. The master host belongs to an unnamed pool by default. To create a resource pool with the CLI, rename the existing nameless pool:

xe pool-param-set name-label=<"New Pool"> uuid=<pool_uuid>

Create the NIC bond on the master as follows:
1. Use the bond-create command to create the bond, specifying the network UUID created in step a and the UUIDs of the PIFs to be bonded, separated by commas. The UUID for the bond is returned:
```
xe bond-create network-uuid=<network_uuid> pif-uuids=<pif_uuid_1>,<pif_uuid_2>
```
  Note
  See Section 4.2.4.2, “Controlling the MAC address of the bond” for details on controlling the MAC address used for the bond PIF.
2. Use the pif-list command to determine the UUID of the new bond PIF:
```
xe pif-list  network-uuid=<network_uuid>
```
3. Use the pif-reconfigure-ip command to configure the desired management interface IP address settings for the bond PIF. See Chapter 8, Command line interface, for more detail on the options available for the pif-reconfigure-ip command.
```
xe pif-reconfigure-ip uuid=<bond_pif_uuid> mode=DHCP
```
4. Use the host-management-reconfigure command to move the management interface from the existing physical PIF to the bond PIF. This step will activate the bond:
```
xe host-management-reconfigure pif-uuid=<bond_pif_uuid>
```
5. Use the pif-reconfigure-ip command to remove the IP address configuration from the non-bonded PIF previously used for the management interface. This step is not strictly necessary but might help reduce confusion when reviewing the host networking configuration.
```
xe pif-reconfigure-ip uuid=<old_management_pif_uuid> mode=None
```
Open a console on a host that you want to join to the pool and run the command:
```
xe pool-join master-address=<host1> master-username=root master-password=<password>
```
The network and bond information is automatically replicated to the new host. However, the management interface is not automatically moved from the host NIC to the bonded NIC. Move the management interface on the host to enable the bond as follows:
1. Use the host-list command to find the UUID of the host being configured:
```
xe host-list
```
2. Use the pif-list command to determine the UUID of bond PIF on the new host. Include the host-uuid parameter to list only the PIFs on the host being configured:
```
xe pif-list network-name-label=<network_name> host-uuid=<host_uuid>
```
3. Use the pif-reconfigure-ip command to configure the desired management interface IP address settings for the bond PIF. See Chapter 8, Command line interface, for more detail on the options available for the pif-reconfigure-ip command. This command must be run directly on the host:
```
xe pif-reconfigure-ip uuid=<bond_pif_uuid> mode=DHCP
```
4. Use the host-management-reconfigure command to move the management interface from the existing physical PIF to the bond PIF. This step activates the bond. This command must be run directly on the host:
```
xe host-management-reconfigure pif-uuid=<bond_pif_uuid>
```
5. Use the pif-reconfigure-ip command to remove the IP address configuration from the non-bonded PIF previously used for the management interface. This step is not strictly necessary but may help reduce confusion when reviewing the host networking configuration. This command must be run directly on the host server:
```
xe pif-reconfigure-ip uuid=<old_mgmt_pif_uuid> mode=None
```
For each additional host you want to join to the pool, repeat steps 3 and 4 to move the management interface on the host and to enable the bond.

4.2.5.2. Adding NIC bonds to an existing pool

Warning

Do not attempt to create network bonds while HA is enabled. The process of bond creation disturbs the in-progress HA heartbeating and causes hosts to self-fence (shut themselves down); subsequently they will likely fail to reboot properly and you will need to run the host-emergency-ha-disable command to recover them.

Note

If you are not using XenCenter for NIC bonding, the quickest way to create pool-wide NIC bonds is to create the bond on the master, and then restart the other pool members. Alternately you can use the service xapi restart command. This causes the bond and VLAN settings on the master to be inherited by each host. The management interface of each host must, however, be manually reconfigured.

When adding a NIC bond to an existing pool, the bond must be manually created on each host in the pool. The steps below can be used to add NIC bonds on both the pool master and other hosts with the following requirements:

All VMs in the pool must be shut down
Add the bond to the pool master first, and then to other hosts.
The bond-create, host-management-reconfigure and host-management-disable commands affect the host on which they are run and so are not suitable for use on one host in a pool to change the configuration of another. Run these commands directly on the console of the host to be affected.

To add NIC bonds to the pool master and other hosts

Use the network-create command to create a new pool-wide network for use with the bonded NICs. This step should only be performed once per pool. The UUID of the new network is returned.

xe network-create name-label=<bond0>

Use XenCenter or the vm-shutdown command to shut down all VMs in the host pool to force all existing VIFs to be unplugged from their current networks. The existing VIFs will be invalid after the bond is enabled.

xe vm-shutdown uuid=<vm_uuid>

Use the host-list command to find the UUID of the host being configured:

xe host-list

Use the pif-list command to determine the UUIDs of the PIFs to use in the bond. Include the host-uuid parameter to list only the PIFs on the host being configured:

xe pif-list host-uuid=<host_uuid>

Use the bond-create command to create the bond, specifying the network UUID created in step 1 and the UUIDs of the PIFs to be bonded, separated by commas. The UUID for the bond is returned.
```
xe bond-create network-uuid=<network_uuid> pif-uuids=<pif_uuid_1>,<pif_uuid_2>
```
Note
See Section 4.2.4.2, “Controlling the MAC address of the bond” for details on controlling the MAC address used for the bond PIF.
Use the pif-list command to determine the UUID of the new bond PIF. Include the host-uuid parameter to list only the PIFs on the host being configured:
```
xe pif-list device=bond0 host-uuid=<host_uuid>
```
Use the pif-reconfigure-ip command to configure the desired management interface IP address settings for the bond PIF. See Chapter 8, Command line interface for more detail on the options available for the pif-reconfigure-ip command. This command must be run directly on the host:
```
xe pif-reconfigure-ip uuid=<bond_pif_uuid> mode=DHCP
```
Use the host-management-reconfigure command to move the management interface from the existing physical PIF to the bond PIF. This step will activate the bond. This command must be run directly on the host:
```
xe host-management-reconfigure pif-uuid=<bond_pif_uuid>
```
Use the pif-reconfigure-ip command to remove the IP address configuration from the non-bonded PIF previously used for the management interface. This step is not strictly necessary, but might help reduce confusion when reviewing the host networking configuration. This command must be run directly on the host:
```
xe pif-reconfigure-ip uuid=<old_management_pif_uuid> mode=None
```
Move existing VMs to the bond network using the vif-destroy and vif-create commands. This step can also be completed using XenCenter by editing the VM configuration and connecting the existing VIFs of the VM to the bond network.
Repeat steps 3 - 10 for other hosts.
Restart the VMs previously shut down.

4.2.6. Configuring a dedicated storage NIC

XenServer allows use of either XenCenter or the xe CLI to configure and dedicate a NIC to specific functions, such as storage traffic.

Assigning a NIC to a specific function will prevent the use of the NIC for other functions such as host management, but requires that the appropriate network configuration be in place in order to ensure the NIC is used for the desired traffic. For example, to dedicate a NIC to storage traffic the NIC, storage target, switch, and/or VLAN must be configured such that the target is only accessible over the assigned NIC. This allows use of standard IP routing to control how traffic is routed between multiple NICs within a XenServer.

Note

Before dedicating a network interface as a storage interface for use with iSCSI or NFS SRs, ensure that the dedicated interface uses a separate IP subnet which is not routable from the main management interface. If this is not enforced, then storage traffic may be directed over the main management interface after a host reboot, due to the order in which network interfaces are initialized.

To assign NIC functions using the xe CLI

Ensure that the PIF is on a separate subnet, or routing is configured to suit your network topology in order to force the desired traffic over the selected PIF.
Setup an IP configuration for the PIF, adding appropriate values for the mode parameter and if using static IP addressing the IP, netmask, gateway, and DNS parameters:
```
xe pif-reconfigure-ip mode=<DHCP | Static> uuid=<pif-uuid>
```

Set the PIF's disallow-unplug parameter to true:

xe pif-param-set disallow-unplug=true uuid=<pif-uuid>

xe pif-param-set other-config:management_purpose="Storage" uuid=<pif-uuid>

If you want to use a storage interface that can be routed from the management interface also (bearing in mind that this configuration is not recommended), then you have two options:

After a host reboot, ensure that the storage interface is correctly configured, and use the xe pbd-unplug and xe pbd-plug commands to reinitialize the storage connections on the host. This will restart the storage connection and route it over the correct interface.
Alternatively, you can use xe pif-forget to remove the interface from the XenServer database, and manually configure it in the control domain. This is an advanced option and requires you to be familiar with how to manually configure Linux networking.

4.2.7. Controlling Quality of Service (QoS)

Citrix Essentials for XenServer allows an optional Quality of Service (QoS) value to be set on VM virtual network interfaces (VIFs) using the CLI. The supported QoS algorithm type is rate limiting, specified as a maximum transfer rate for the VIF in Kb per second.

For example, to limit a VIF to a maximum transfer rate of 100kb/s, use the vif-param-set command:

xe vif-param-set uuid=<vif_uuid> qos_algorithm_type=ratelimit
xe vif-param-set uuid=<vif_uuid> qos_algorithm_params:kbps=100

4.2.8. Changing networking configuration options

This section discusses how to change the networking configuration of a XenServer host. This includes:

changing the hostname
adding or removing DNS servers
changing IP addresses
changing which NIC is used as the management interface
adding a new physical NIC to the server

4.2.8.1. Hostname

The system hostname is defined in the pool-wide database and modified using the xe host-set-hostname-live CLI command as follows:

xe host-set-hostname-live uuid=<host_uuid> host-name=example

The underlying control domain hostname changes dynamically to reflect the new hostname.

4.2.8.2. DNS servers

To add or remove DNS servers in the IP addressing configuration of a XenServer host, use the pif-reconfigure-ip command. For example, for a PIF with a static IP:

pif-reconfigure-ip uuid=<pif_uuid> mode=static DNS=<new_dns_ip>

4.2.8.3. Changing IP address configuration for a standalone host

Network interface configuration can be changed using the xe CLI. The underlying network configuration scripts should not be modified directly.

To modify the IP address configuration of a PIF, use the pif-reconfigure-ip CLI command. See Section 8.4.11.4, “pif-reconfigure-ip” for details on the parameters of the pif-reconfigure-ip command.

Note

See Section 4.2.8.4, “Changing IP address configuration in resource pools” for details on changing host IP addresses in resource pools.

4.2.8.4. Changing IP address configuration in resource pools

XenServer hosts in resource pools have a single management IP address used for management and communication to and from other hosts in the pool. The steps required to change the IP address of a host's management interface are different for master and other hosts.

Note

Caution should be used when changing the IP address of a server, and other networking parameters. Depending upon the network topology and the change being made, connections to network storage may be lost. If this happens the storage must be replugged using the Repair Storage function in XenCenter, or the pbd-plug command using the CLI. For this reason, it may be advisable to migrate VMs away from the server before changing its IP configuration.

Changing the IP address of a pool member host

Use the pif-reconfigure-ip CLI command to set the IP address as desired. See Chapter 8, Command line interface for details on the parameters of the pif-reconfigure-ip command:
```
xe pif-reconfigure-ip uuid=<pif_uuid> mode=DHCP
```
Use the host-list CLI command to confirm that the member host has successfully reconnected to the master host by checking that all the other XenServer hosts in the pool are visible:
```
xe host-list
```

Changing the IP address of the master XenServer host requires additional steps because each of the member hosts uses the advertised IP address of the pool master for communication and will not know how to contact the master when its IP address changes.

Whenever possible, use a dedicated IP address that is not likely to change for the lifetime of the pool for pool masters.

To change the IP address of a pool master host

Use the pif-reconfigure-ip CLI command to set the IP address as desired. See Chapter 8, Command line interface for details on the parameters of the pif-reconfigure-ip command:
```
xe pif-reconfigure-ip uuid=<pif_uuid> mode=DHCP
```
When the IP address of the pool master host is changed, all member hosts will enter into an emergency mode when they fail to contact the master host.
On the master XenServer host, use the pool-recover-slaves command to force the master to contact each of the member hosts and inform them of the new master IP address:
```
xe pool-recover-slaves
```

Refer to Section 6.4.2, “Master failures” for more information on emergency mode.

4.2.8.5. Management interface

When XenServer is installed on a host with multiple NICs, one NIC is selected for use as the management interface. The management interface is used for XenCenter connections to the host and for host-to-host communication.

To change the NIC used for the management interface

Use the pif-list command to determine which PIF corresponds to the NIC to be used as the management interface. The UUID of each PIF is returned.

xe pif-list

Use the pif-param-list command to verify the IP addressing configuration for the PIF that will be used for the management interface. If necessary, use the pif-reconfigure-ip command to configure IP addressing for the PIF to be used. See Chapter 8, Command line interface for more detail on the options available for the pif-reconfigure-ip command.
```
xe pif-param-list uuid=<pif_uuid>
```
Use the host-management-reconfigure CLI command to change the PIF used for the management interface. If this host is part of a resource pool, this command must be issued on the member host console:
```
xe host-management-reconfigure pif-uuid=<pif_uuid>
```

Warning

Putting the management interface on a VLAN network is not supported.

4.2.8.6. Disabling management access

To disable remote access to the management console entirely, use the host-management-disable CLI command.

Warning

Once the management interface is disabled, you will have to log in on the physical host console to perform management tasks and external interfaces such as XenCenter will no longer work.

4.2.8.7. Adding a new physical NIC

Install a new physical NIC on a XenServer host in the usual manner. Then, after restarting the server, run the xe CLI command pif-scan to cause a new PIF object to be created for the new NIC.

4.2.9. NIC/PIF ordering in resource pools

It is possible for physical NIC devices to be discovered in different orders on different servers even though the servers contain the same hardware. Verifying NIC ordering is recommended before using the pooling features of XenServer.

4.2.9.1. Verifying NIC ordering

Use the pif-list command to verify that NIC ordering is consistent across your XenServer hosts. Review the MAC address and carrier (link state) parameters associated with each PIF to verify that the devices discovered (eth0, eth1, etc.) correspond to the appropriate physical port on the server.

xe pif-list params=uuid,device,MAC,currently-attached,carrier,management, \
IP-configuration-mode

uuid ( RO)                     : 1ef8209d-5db5-cf69-3fe6-0e8d24f8f518
                   device ( RO): eth0
                      MAC ( RO): 00:19:bb:2d:7e:8a
       currently-attached ( RO): true
               management ( RO): true
    IP-configuration-mode ( RO): DHCP
                  carrier ( RO): true


uuid ( RO)                     : 829fd476-2bbb-67bb-139f-d607c09e9110
                   device ( RO): eth1
                      MAC ( RO): 00:19:bb:2d:7e:7a
       currently-attached ( RO): false
               management ( RO): false
    IP-configuration-mode ( RO): None
                  carrier ( RO): true

If the hosts have already been joined in a pool, add the host-uuid parameter to the pif-list command to scope the results to the PIFs on a given host.

4.2.9.2. Re-ordering NICs

It is not possible to directly rename a PIF, although you can use the pif-forget and pif-introduce commands to achieve the same effect with the following restrictions:

The XenServer host must be standalone and not joined to a resource pool.
Re-ordering a PIF configured as the management interface of the host requires additional steps which are included in the example below. Because the management interface must first be disabled the commands must be entered directly on the host console.

For the example configuration shown above use the following steps to change the NIC ordering so that eth0 corresponds to the device with a MAC address of 00:19:bb:2d:7e:7a:

Use XenCenter or the vm-shutdown command to shut down all VMs in the pool to force existing VIFs to be unplugged from their networks.

xe vm-shutdown uuid=<vm_uuid>

Use the host-management-disable command to disable the management interface:

xe host-management-disable

Use the pif-forget command to remove the two incorrect PIF records:

xe pif-forget uuid=1ef8209d-5db5-cf69-3fe6-0e8d24f8f518
xe pif-forget uuid=829fd476-2bbb-67bb-139f-d607c09e9110

Use the pif-introduce command to re-introduce the devices with the desired naming:

xe pif-introduce device=eth0 host-uuid=<host_uuid> mac=00:19:bb:2d:7e:7a
xe pif-introduce device=eth1 host-uuid=<host_uuid> mac=00:19:bb:2d:7e:8a

Use the pif-list command again to verify the new configuration:

xe pif-list params=uuid,device,MAC

Use the pif-reconfigure-ip command to reset the management interface IP addressing configuration. See Chapter 8, Command line interface for details on the parameters of the pif-reconfigure-ip command.
```
xe pif-reconfigure-ip uuid=<728d9e7f-62ed-a477-2c71-3974d75972eb> mode=dhcp
```
Use the host-management-reconfigure command to set the management interface to the desired PIF and re-enable external management connectivity to the host:
```
xe host-management-reconfigure pif-uuid=<728d9e7f-62ed-a477-2c71-3974d75972eb>
```

4.3. Networking Troubleshooting

If you are having problems with configuring networking, first ensure that you have not directly modified any of the control domain ifcfg-* files directly. These files are directly managed by the control domain host agent, and changes will be overwritten.

4.3.1. Diagnosing network corruption

Some models of network cards require firmware upgrades from the vendor to work reliably under load, or when certain optimizations are turned on. If you are seeing corrupted traffic to VMs, then you should first try to obtain the latest recommended firmware from your vendor and apply a BIOS update.

If the problem still persists, then you can use the CLI to disable receive / transmit offload optimizations on the physical interface.

Warning

Disabling receive / transmit offload optimizations can result in a performance loss and / or increased CPU usage.

First, determine the UUID of the physical interface. You can filter on the device field as follows:

xe pif-list device=eth0

Next, set the following parameter on the PIF to disable TX offload:

xe pif-param-set uuid=<pif_uuid> other-config:ethtool-tx=off

Finally, re-plug the PIF or reboot the host for the change to take effect.

4.3.2. Recovering from a bad network configuration

In some cases it is possible to render networking unusable by creating an incorrect configuration. This is particularly true when attempting to make network configuration changes on a member XenServer host.

If a loss of networking occurs, the following notes may be useful in recovering and regaining network connectivity:

Citrix recommends that you ensure networking configuration is set up correctly before creating a resource pool, as it is usually easier to recover from a bad configuration in a non-pooled state.
The host-management-reconfigure and host-management-disable commands affect the XenServer host on which they are run and so are not suitable for use on one host in a pool to change the configuration of another. Run these commands directly on the console of the XenServer host to be affected, or use the xe -s, -u, and -pw remote connection options.
When the xapi service starts, it will apply configuration to the management interface first. The name of the management interface is saved in the /etc/xensource-inventory file. In extreme cases, you can stop the xapi service by running service xapi stop at the console, edit the inventory file to set the management interface to a safe default, and then ensure that the ifcfg files in /etc/sysconfig/network-scripts have correct configurations for a minimal network configuration (including one interface and one bridge; for example, eth0 on the xenbr0 bridge).

Chapter 5. Workload Balancing

5.1. Workload Balancing Overview

5.1.1. Workload Balancing Basic Concepts

5.2. Designing Your Workload Balancing Deployment

5.2.1. Deploying One Server
5.2.2. Planning for Future Growth
5.2.3. Increasing Availability
5.2.4. Multiple Server Deployments
5.2.5. Workload Balancing Security

5.3. Workload Balancing Installation Overview

5.3.1. Workload Balancing System Requirements
5.3.2. Workload Balancing Data Store Requirements
5.3.3. Operating System Language Support
5.3.4. Preinstallation Considerations
5.3.5. Installing Workload Balancing

5.4. Windows Installer Commands for Workload Balancing

5.4.1. ADDLOCAL
5.4.2. CERT_CHOICE
5.4.3. CERTNAMEPICKED
5.4.4. DATABASESERVER
5.4.5. DBNAME
5.4.6. DBUSERNAME
5.4.7. DBPASSWORD
5.4.8. EXPORTCERT
5.4.9. EXPORTCERT_FQFN
5.4.10. HTTPS_PORT
5.4.11. INSTALLDIR
5.4.12. PREREQUISITES_PASSED
5.4.13. RECOVERYMODEL
5.4.14. USERORGROUPACCOUNT
5.4.15. WEBSERVICE_USER_CB
5.4.16. WINDOWS_AUTH

5.5. Initializing and Configuring Workload Balancing

5.5.1. Initialization Overview
5.5.2. To initialize Workload Balancing
5.5.3. To edit the Workload Balancing configuration for a pool
5.5.4. Authorization for Workload Balancing
5.5.5. Configuring Antivirus Software
5.5.6. Changing the Placement Strategy
5.5.7. Changing the Performance Thresholds and Metric Weighting

5.6. Accepting Optimization Recommendations

5.6.1. To accept an optimization recommendation

5.7. Choosing an Optimal Server for VM Initial Placement, Migrate, and Resume

5.7.1. To start a virtual machine on the optimal server

5.8. Entering Maintenance Mode with Workload Balancing Enabled

5.8.1. To enter maintenance mode with Workload Balancing enabled

5.9. Working with Workload Balancing Reports

5.9.1. Introduction
5.9.2. Types of Workload Balancing Reports
5.9.3. Using Workload Balancing Reports for Tasks
5.9.4. Creating Workload Balancing Reports
5.9.5. Generating Workload Balancing Reports
5.9.6. Workload Balancing Report Glossary

5.10. Administering Workload Balancing

5.10.1. Disabling Workload Balancing on a Resource Pool
5.10.2. Reconfiguring a Resource Pool to Use Another WLB Server
5.10.3. Uninstalling Workload Balancing

5.11. Troubleshooting Workload Balancing

5.11.1. General Troubleshooting Tips
5.11.2. Error Messages
5.11.3. Issues Installing Workload Balancing
5.11.4. Issues Initializing Workload Balancing
5.11.5. Issues Starting Workload Balancing
5.11.6. Workload Balancing Connection Errors
5.11.7. Issues Changing Workload Balancing Servers

5.1. Workload Balancing Overview

Workload Balancing is a XenServer feature that helps you balance virtual machine workloads across hosts and locate VMs on the best possible servers for their workload in a resource pool. When Workload Balancing places a virtual machine, it determines the best host on which to start a virtual machine or it rebalances the workload across hosts in a pool. For example, Workload Balancing lets you determine where to:

Start a virtual machine
Resume a virtual machine that you powered off
Move virtual machines when a host fails

When Workload Balancing is enabled, if you put a host into Maintenance Mode, Workload Balancing selects the optimal server for each of the host's virtual machines. For virtual machines taken offline, Workload Balancing provides recommendations to help you restart virtual machines on the optimal server in the pool.

Workload Balancing also lets you balance virtual-machine workloads across hosts in a XenServer resource pool. When the workload on a host exceeds the level you set as acceptable (the threshold), Workload Balancing will make recommendations to move part of its workload (for example, one or two virtual machines) to a less-taxed host in the same pool. It does this by evaluating the existing workloads on hosts against resource performance on other hosts.

You can also use Workload Balancing to help determine if you can power off hosts at certain times of day.

Workload Balancing performs these tasks by analyzing XenServer resource-pool metrics and recommending optimizations. You decide if you want these recommendations geared towards resource performance or hardware density. You can fine-tune the weighting of individual resource metrics (CPU, network, memory, and disk) so that the placement recommendations and critical thresholds align with your environment's needs.

To help you perform capacity planning, Workload Balancing provides historical reports about host and pool health, optimization and virtual-machine performance, and virtual-machine motion history.

5.1.1. Workload Balancing Basic Concepts

Workload Balancing captures data for resource performance on virtual machines and physical hosts. It uses this data, combined with the preferences you set, to provide optimization and placement recommendations. Workload Balancing stores performance data in a SQL Server database: the longer Workload Balancing runs the more precise its recommendations become.

Workload Balancing recommends moving virtual-machine workloads across a pool to get the maximum efficiency, which means either performance or density depending on your goals. Within a Workload Balancing context:

Performance refers to the usage of physical resources on a host (for example, the CPU, memory, network, and disk utilization on a host). When you set Workload Balancing to maximize performance, it recommends placing virtual machines to ensure the maximum amount of resources are available for each virtual machine.
Density refers to the number of virtual machines on a host. When you set Workload Balancing to maximize density, it recommends placing virtual machines to ensure they have adequate computing power so you can reduce the number of hosts powered on in a pool.

Workload Balancing configuration preferences include settings for placement (performance or density), virtual CPUs, and performance thresholds.

Workload Balancing does not conflict with settings you already specified for High Availability. Citrix designed the features to work in conjunction with each other.

5.1.1.1. Workload Balancing Component Overview

The Workload Balancing software is a collection of services and components that let you manage all of Workload Balancing's basic functions, such as manage workload and displaying reports. You can install the Workload Balancing services on one computer (physical or virtual) or multiple computers. A Workload Balancing server can manage more than one resource pool.

Workload Balancing consists of the following components:

Workload Balancing server. Collects data from the virtual machines and their hosts and writes the data to the data store. This service is also referred to as the "data collector."
Data Store. A Microsoft SQL Server or SQL Server Express database that stores performance and configuration data.

For more information about Workload Balancing components for large deployments with multiple servers, see Multiple Server Deployments.

5.2. Designing Your Workload Balancing Deployment

You can install Workload Balancing on one computer (physical or virtual) or distribute the components across multiple computers. The three most common deployment configurations are the following:

All components are installed on a single server
The data collector is installed on a dedicated server
All components are installed on a single server, but the data store is installed on central database server

Because one data collector can monitor multiple resource pools, you do not need multiple data collectors to monitor multiple pools.

5.2.1. Deploying One Server

Depending on your environment and goals, you can install Workload Balancing and the data store on one server. In this configuration, one data collector monitors all the resource pools.

The following table shows the advantages and disadvantages to a single-server deployment:

Advantages	Disadvantages
Simple installation and configuration. No Windows domain requirement.	Single point of failure.

5.2.2. Planning for Future Growth

If you anticipate that you will want to add more resource pools in the future, consider designing your Workload Balancing deployment so that it supports growth and scalability. Consider:

Using SQL Server for the data store. In large environments, consider using SQL Server for the data store instead of SQL Server Express. Because SQL Server Express has a 4GB disk-space limit, Workload Balancing limits the data store to 3.5GB when installed on this database. SQL Server has no preset disk-space limitation.
Deploying the data store on a dedicated server. If you deploy SQL Server on a dedicated server (instead of collocating it on the same computer as the other Workload Balancing services), you can let it use more memory.

5.2.3. Increasing Availability

If Workload Balancing's recommendations or reports are critical in your environment, consider implementing strategies to ensure high availability, such as one of the following:

Installing multiple data collectors, so there is not a single point of failure.
Configuring Microsoft clustering. This is the only true failover configuration for single-server deployments. However, Workload Balancing services are not "cluster aware," so if the primary server in the cluster fails, any pending requests are lost when the secondary server in the cluster takes over.
Making Workload Balancing part of a XenServer resource pool with High Availability enabled.

5.2.4. Multiple Server Deployments

In some situations, you might need to deploy Workload Balancing on multiple servers. When you deploy Workload Balancing on multiple servers, you place its key services on one more servers:

Data Collection Manager service. Collects data from the virtual machines and their hosts and writes the data to the data store. This service is also referred to as the "data collector."
Web Service Host. Facilitates communications between the XenServer and the Analysis Engine. Requires a security certificate, which you can create or provide during Setup.
Analysis Engine service. Monitors resource pools and determines if a resource pool needs optimizations.

The size of your XenServer environment affects your Workload Balancing design. Since every environment is different, the size definitions that follow are examples of environments of that size:

Size	Example
Small	One resource pool with 2 hosts and 8 virtual machines
Medium	Two resource pools with 6 hosts and 8 virtual machines per pool
Large	Five resource pools with 16 hosts and 64 virtual machines per pool

5.2.4.1. Deploying Multiple Servers

Having multiple servers for Workload Balancing's services may be necessary in large environments. For example, having multiple servers may reduce "bottlenecks." If you decide to deploy Workload Balancing's services on multiple computers, all servers must be members of mutually trusted Active Directory domains.

Advantages	Disadvantages
Provides better scalability. Can monitor more resource pools.	More equipment to manage and, consequently, more expense.

5.2.4.2. Deploying Multiple Data Collectors

Workload Balancing supports multiple data collectors, which might be beneficial in environments with many resource pools. When you deploy multiple data collectors, the data collectors work together to ensure all XenServer pools are being monitored at all times.

All data collectors collect data from their own resource pools. One data collector, referred to as the master, also does the following:

Checks for configuration changes and determines the relationships between resource pools and data collectors
Checks for new XenServer resource pools to monitor and assigns these pools to a data collector
Monitors the health of the other data collectors

If a data collector goes offline or you add a new resource pool, the master data collector rebalances the workload across the data collectors. If the master data collector goes offline, another data collector assumes the role of the master.

5.2.4.3. Considering Large Environments

In large environments, consider the following:

When you install Workload Balancing on SQL Server Express, Workload Balancing limits the size of the metrics data to 3.5GB. If the data grows beyond this size, Workload Balancing starts grooming the data, deleting older data, automatically.
Citrix recommends putting the data store on one computer and the Workload Balancing services on another computer.
For Workload Balancing data-store operations, memory utilization is the largest consideration.

5.2.5. Workload Balancing Security

Citrix designed Workload Balancing to operate in a variety of environments, and Citrix recommends properly securing the installation. The steps required vary according to your planned deployment and your organization's security policies. This topic provides information about the available options and makes recommendations.

Important

Citrix does not recommend changing the privileges or accounts under which the Workload Balancing services run.

5.2.5.1. Encryption Requirements

XenServer communicates with Workload Balancing using HTTPS. Consequently, you must create or install an SSL/TLS certificate when you install Workload Balancing (or the Web Services Host, if it is on a separate server). You can either use a certificate from a Trusted Authority or create a self-signed certificate using Workload Balancing Setup.

The self-signed certificate Workload Balancing Setup creates is not from a Trusted Authority. If you do not want to use this self-signed certificate, prepare a certificate before you begin Setup and specify that certificate when prompted.

If desired, during Workload Balancing Setup, you can export the certificate so that you can import it into XenServer after Setup.

Note

If you create a self-signed certificate during Workload Balancing Setup, Citrix recommends that you eventually replace this certificate with one from a Trusted Authority.

5.2.5.2. Domain Considerations

When deploying Workload Balancing, your environment determines your domain and security requirements.

If your Workload Balancing services are on multiple computers, the computers must be part of a domain.
If your Workload Balancing components are in separate domains, you must configure trust relationships between those domains.

5.2.5.3. SQL Server Authentication Requirements

When you install SQL Server or SQL Server Express, you must configure Windows authentication (also known as Integrated Windows Authentication). Workload Balancing does not support SQL Server Authentication.

5.3. Workload Balancing Installation Overview

Workload Balancing is a XenServer feature that helps manage virtual-machine workloads within a XenServer environment. Workload Balancing requires that you:

Install SQL Server or SQL Server Express.
Install Workload Balancing on one or more computers (physical or virtual). See Section 5.2, “Designing Your Workload Balancing Deployment”.

Typically, you install and configure Workload Balancing after you have created one or more XenServer resource pools in your environment.

You install all Workload Balancing functions, such as the Workload Balancing data store, the Analysis Engine, and the Web Service Host, from Setup.

You can install Workload Balancing in one of two ways:

Installation Wizard. Start the installation wizard from Setup.exe. Citrix suggests installing Workload Balancing from the installation wizard because this method checks your system meets the installation requirements.
Command Line. If you install Workload Balancing from the command line, the prerequisites are not checked. For Msiexec properties, see Section 5.4, “Windows Installer Commands for Workload Balancing”.

When you install the Workload Balancing data store, Setup creates the database. You do not need to run Workload Balancing Setup locally on the database server: Setup supports installing the data store across a network.

If you are installing Workload Balancing services as components on separate computers, you must install the database component before the Workload Balancing services.

After installation, you must configure Workload Balancing before you can use it to optimize workloads. For information, see Section 5.5, “Initializing and Configuring Workload Balancing”.

For information about System Requirements, see Section 5.3.1, “Workload Balancing System Requirements”. For installation instructions, see Section 5.3.5, “Installing Workload Balancing”.

5.3.1. Workload Balancing System Requirements

This topic provides system requirements for:

For information about data store requirements, see Section 5.3.2, “Workload Balancing Data Store Requirements”.

5.3.1.1. Supported XenServer Versions

XenServer 5.5

5.3.1.2. Supported Operating Systems

Unless otherwise noted, Workload Balancing components run on the following operating systems (32-bit and 64-bit):

Windows Server 2008
Windows Server 2003, Service Pack 2
Windows Vista
Windows XP Professional, Service Pack 2 or Service Pack 3

If you are installing with the User Account Control (UAC) enabled, see Microsoft's documentation.

5.3.1.3. Recommended Hardware

Unless otherwise noted, Workload Balancing components require the following hardware (32-bit and 64-bit):

CPU: 2GHz or faster
Memory: 2GB recommended (1GB of RAM required)
Disk Space: 20GB (minimum)

When all Workload Balancing services are installed on the same server, Citrix recommends that the server have a minimum of a dual-core processor.

5.3.1.4. Data Collection Manager

Operating System Components	Microsoft .NET Framework 3.5, Service Pack 1 or higher
Hard Drive	1GB

5.3.1.5. Analysis Engine

Operating System Components

Microsoft .NET Framework 3.5, Service Pack 1 or higher

5.3.1.6. Web Service Host

Operating System Components

Microsoft .NET Framework 3.5, Service Pack 1 or higher

5.3.2. Workload Balancing Data Store Requirements

This topic provides information about the SQL Server versions and configurations that Workload Balancing supports. It also provides information about additional compatibility and authentication requirements.

5.3.2.1. Installation Requirements for SQL Server

In addition to the prerequisites SQL Server and SQL Server Express require, the data store also requires the following:

Note

In this topic, the term SQL Server refers to both SQL Server and SQL Server Express unless the version is mentioned explicitly.

Operating System	One of the following, as required by your SQL Server edition: Windows Server 2008 Windows Server 2003, Service Pack 1 or higher Windows Vista and Windows XP Professional (for SQL Server Express)
Database	The 32-bit or 64-bit edition of: SQL Server 2008 Express. The 32-bit edition is available on the Workload Balancing installation media in the sql folder. SQL Server 2008 (Standard edition or better) SQL Server 2005, Service Pack 1 or higher (Standard edition or better) Note Windows Server 2008 servers require SQL Server 2005, Service Pack 2 or higher.
Required Configurations	Configure SQL Server for case-insensitive collation. Workload Balancing does not currently support case-sensitive collation. Microsoft SQL Server 2005 Backward Compatibility Components. See Section 5.3.2.3, “Backwards Compatibility Requirement for SQL Server 2008” for more information.
Hard Drive	SQL Server Express: 5GB SQL Server: 20GB

5.3.2.2. SQL Server Database Authentication Requirements

During installation, Setup must connect and authenticate to the database server to create the data store. Configure the SQL Server database instance to use either:

Windows Authentication mode, or
SQL Server and Windows Authentication mode (Mixed Mode authentication)

If you create an account on the database for use during Setup, the account must have sysadmin privileges for the database instance where you want to create the Workload Balancing data store.

5.3.2.3. Backwards Compatibility Requirement for SQL Server 2008

After installing SQL Server Express 2008 or SQL Server 2008, you must install the SQL Server 2005 Backward Compatibility Components on all Workload Balancing computers before running Workload Balancing Setup. The Backward Compatibility components let Workload Balancing Setup configure the database.

The Workload Balancing installation media includes the 32-bit editions of SQL Server Express 2008 and the SQL Server 2005 Backward Compatibility Components.

While some SQL Server editions may include the Backward Compatibility components with their installation programs, their Setup program might not install them by default.
You can also obtain the Backward Compatibility components from the download page for the latest Microsoft SQL Server 2008 Feature Pack.

Install the files in the sql folder in the following order:

en_sql_server_2008_express_with_tools_x86.exe. Installs SQL Server Express, 32-bit edition. Requires installing Microsoft .NET Framework 3.5, Service Pack 1 first.
SQLServer2005_BC.msi. Installs the SQL Server 2005 Backward Compatibility Components for 32-bit computers.

5.3.3. Operating System Language Support

Workload Balancing is supported on the following operating system languages:

US English
Japanese (Native JP)

Note

In configurations where the database and Web server are installed on separate servers, the operating system languages must match on both computers.

5.3.4. Preinstallation Considerations

You may need to configure software in your environment so that Workload Balancing can function correctly. Review the following considerations and determine if they apply to your environment. Also, check the XenServer readme for additional, late-breaking release-specific requirements.

Account for Workload Balancing. Before Setup, you must create a user account for XenServer to use to connect to Workload Balancing (specifically the Web Service Host service). This user account can be either a domain account or an account local to the computer running Workload Balancing (or the Web Service Host service).
Important
When you create this account in Windows, Citrix suggests enabling the Password never expires option.
During Setup, you must specify the authorization type (a single user or group) and the user or group with permissions to make requests of the Web Service Host service. For additional information, see Section 5.5.4, “Authorization for Workload Balancing ”.
SSL/TLS Certificate. XenServer and Workload Balancing communicate over HTTPS. Consequently, during Workload Balancing Setup, you must provide either an SSL/TLS certificate from a Trusted Authority or create a self-signed certificate.
Group Policy. If the server on which you are installing Workload Balancing is a member of a Group Policy Organizational Unit, ensure that current or scheduled, future policies do not prohibit Workload Balancing or its services from running.

Note

In addition, review the applicable release notes for release-specific configuration information.

5.3.5. Installing Workload Balancing

Before installing Workload Balancing, you must:

Install a SQL Server or SQL Server Express database as described in Workload Balancing Data Store Requirements.
Have a login on the SQL Server database instance that has SQL Login creation privileges. For SQL Server Authentication, the account needs sysadmin privileges.
Create an account for Workload Balancing, as described in Preinstallation Considerations and have its name on hand.
Configure all Workload Balancing servers to meet the system requirements described in Workload Balancing System Requirements.

After Setup is finished installing Workload Balancing, verify that it configure Workload Balancing before it begins gathering data and making recommendations.

5.3.5.1. To install Workload Balancing on a single server

The following procedure installs Workload Balancing and all of its services on one computer:

Launch the Workload Balancing Setup wizard from Autorun.exe, and select the Workload Balancing installation option.
After the initial Welcome page appears, click Next.
In the Setup Type page, select Workload Balancing Services and Data Store, and click Next. This option lets you install Workload Balancing, including the Web Services Host, Analysis Engine, and Data Collection Manager services. After you click Next, Workload Balancing Setup verifies that your system has the correct prerequisites.
Accept the End-User License Agreement.
In the Component Selection page, select all of the following components:
In the Database Server page, in the SQL Server Selection section, select one of the following:
- Enter the name of a database server . Lets you type the name of the database server that will host the data store. Use this option to specify an instance name.
  Note
  If you installed SQL Express and specified an instance name, append the server name with \yourinstancename. If you installed SQL Express without specifying an instance name, append the server name with \sqlexpress.
- Choose an existing database server . Lets you select the database server from a list of servers Workload Balancing Setup detected on your network. Use the first option (Enter the name of a database) if you specified an instance name.
In the Install Using section, select one of the following methods of authentication:
- Windows Authentication . This option uses your current credentials (that is, the Windows credentials you used to log on to the computer on which you are installing Workload Balancing). To select this option, your current Windows credentials must have been added as a login to the SQL Server database server (instance).
- SQL Server Authentication . To select this option, you must have configured SQL Server to support Mixed Mode authentication.
  Note
  Citrix recommends clicking Test Connect to ensure Setup can use the credentials you provided to contact the database server.
In the Database Information page, select Install a new Workload Balancing data store and type the name you want to assign to the Workload Balancing database in SQL Server. The default database name is WorkloadBalancing.
In the Web Service Host Account Information page, select HTTPS end point (selected by default). Edit the port number, if necessary; the port is set to 8012 by default.
Note
If you are using Workload Balancing with XenServer, you must select HTTPS end points. XenServer can only communicate with the Workload Balancing feature over SSL/TLS. If you change the port here, you must also change it on XenServer using either the Configure Workload Balancing wizard or the XE commands.
For the account (on the Workload Balancing server) that XenServer will use to connect to Workload Balancing, select the authorization type, User or Group, and type one of the following :
- User name. Enter the name of the account you created for XenServer (for example, workloadbalancing_user).
- Group name. Enter the group name for the account you created. Specifying a group name lets you specify a group of users that have been granted permission to connect to the Web Service Host on the Workload Balancing server. Specifying a group name lets more than one person in your organization log on to Workload Balancing with their own credentials. (Otherwise, you will need to provide all users with the same set of credentials to use for Workload Balancing.)
Specifying the authorization type lets Workload Balancing recognize the XenServer's connection. For more information, see Section 5.5.4, “Authorization for Workload Balancing ”. You do not specify the password until you configure Workload Balancing.
In the SSL/TLS Certificate page, select one of the following certificate options:
Click Install.

5.3.5.2. To install the data store separately

The following procedure installs the Workload Balancing data store only:

From any server with network access to the database, launch the Workload Balancing Setup wizard from Autorun.exe, and select the WorkloadBalancing installation option.
After the initial Welcome page appears, click Next.
In the Setup Type page, select Workload Balancing Database Only, and click Next.This option lets you install the Workload Balancing data store only. After you click Next, Workload Balancing Setup verifies that your system has the correct prerequisites.
Accept the End-User License Agreement, and click Next.
In the Component Selection page, accept the default installation and click Next. This option creates and configures a database for the Workload Balancing data store.
In the Database Server page, in the SQL Server Selection section, select one of the following:
- Enter the name of a database server. Lets you type the name of the database server that will host the data store. Use this option to specify an instance name.
  Note
  If you installed SQL Express and specified an instance name, append the server name with \yourinstancename. If you installed SQL Express without specifying an instance name, append the server name with \sqlexpress.
- Choose an existing database server. Lets you select the database server from a list of servers Workload Balancing Setup detected on your network.
In the Install Using section, select one of the following methods of authentication:
- Windows Authentication. This option uses your current credentials (that is, the Windows credentials you used to log on to the computer on which you are installing Workload Balancing). To select this option, your current Windows credentials must have been added as a login to the SQL Server database server (instance).
- SQL Server Authentication. To select this option, you must have configured SQL Server to support Mixed Mode authentication.
  Note
  Citrix recommends clicking Test Connect to ensure Setup can use the credentials you provided to contact the database server.
In the Database Information page, select Install a new Workload Balancing data store and type the name you want to assign to the Workload Balancing database in SQL Server. The default database name is WorkloadBalancing.
Click Install to install the data store.

5.3.5.3. To install Workload Balancing components separately

The following procedure installs Workload Balancing services on separate computers:

Launch the Workload Balancing Setup wizard from Autorun.exe, and select the WorkloadBalancing installation option.
After the initial Welcome page appears, click Next.
In the Setup Type page, select Workload Balancing Server Services and Database.This option lets you install Workload Balancing, including the Web Services Host, Analysis Engine, and Data Collection Manager services.Workload Balancing Setup verifies that your system has the correct prerequisites.
Accept the End-User License Agreement, and click Next.
In the Component Selection page, select the services you want to install:
In the Database Server page, in the SQL Server Selection section, select one of the following:
- Enter the name of a database server. Lets you type the name of the database server that is hosting the data store.
  Note
  If you installed SQL Express and specified an instance name, append the server name with \yourinstancename. If you installed SQL Express without specifying an instance name, append the server name with \sqlexpress.
- Choose an existing database server. Lets you select the database server from a list of servers Workload Balancing Setup detected on your network.
Note
Citrix recommends clicking Test Connect to ensure Setup can use the credentials you provided to contact the database server successfully.
In the Web Service Information page, select HTTPS end point (selected by default) and edit the port number, if necessary. The port is set to 8012 by default.
Note
If you are using Workload Balancing with XenServer, you must select HTTPS end points. XenServer can only communicate with the Workload Balancing feature over SSL/TLS. If you change the port here, you must also change it on XenServer using either the Configure Workload Balancing wizard or the XE commands.
For the account (on the Workload Balancing server) that XenServer will use to connect to Workload Balancing, select the authorization type, User or Group, and type one of the following:
In the SSL/TLS Certificate page, select one of the following certificate options:
Click Install.

5.3.5.3.1. To verify your Workload Balancing installation

Workload Balancing Setup does not install an icon in the Windows Start menu. Use this procedure to verify that Workload Balancing installed correctly before trying to connect to Workload Balancing with the Workload Balancing Configuration wizard.

Verify Windows Add or Remove Programs (Windows XP) lists Citrix Workload Balancing in its in the list of currently installed programs.
Check for the following services in the Windows Services panel:
All of these services must be started and running before you start configuring Workload Balancing.
If Workload Balancing appears to be missing, check the installation log to see if it installed successfully:
- If you used the Setup wizard, the log is at %Documents and Settings%\username\Local Settings\Temp\msibootstrapper2CSM_MSI_Install.log (by default). On Windows Vista and Windows Server 2008, this log is at %Users%\username\AppData\Local\Temp\msibootstrapper2CSM_MSI_Install.log. User name is the name of the user logged on during installation.
- If you used the Setup properties (Msiexec), the log is at C:\log.txt (by default) or wherever you specified for Setup to create it.

5.4. Windows Installer Commands for Workload Balancing

The Workload Balancing installation supports using the Msiexec command for Setup. The Msiexec command lets you install, modify, and perform operations on Windows Installer (.msi) packages from the command line.

Set properties by adding Property=”value” on the command line after other switches and parameters.

The following sample command line performs a full installation of the Workload Balancing Windows Installer package and creates a log file to capture information about this operation.

msiexec.exe /I C:\path-to-msi\workloadbalancingx64.msi /quiet 
PREREQUISITES_PASSED="1" 
DBNAME="WorkloadBalancing1" 
DATABASESERVER="WLB-DB-SERVER\INSTANCENAME" 
HTTPS_PORT="8012" 
WEBSERVICE_USER_CB="0" 
USERORGROUPACCOUNT="domain\WLBgroup" 
CERT_CHOICE="0" 
CERTNAMEPICKED="cn=wlb-cert1" 
EXPORTCERT=1
EXPORTCERT_FQFN="C:\Certificates\WLBCert.cer"
INSTALLDIR="C:\Program Files\Citrix\WLB" 
ADDLOCAL="Database,Complete,Services,DataCollection,
Analysis_Engine,DWM_Web_Service" /l*v log.txt

There are two Workload Balancing Windows Installer packages: workloadbalancing.msi and workloadbalancingx64.msi. If you are installing Workload Balancing on a 64-bit operating system, specify workloadbalancingx64.msi.

To see if Workload Balancing Setup succeeded, see Section 5.3.5.3.1, “To verify your Workload Balancing installation”.

Important

Workload Balancing Setup does not provide error messages if you are installing Workload Balancing using Windows Installer commands if the system is missing prerequisites. Instead, installation fails.

5.4.1. ADDLOCAL

5.4.1.1. Definition

Specifies one or more Workload Balancing features to install. The values of ADDLOCAL are Workload Balancing components and services.

5.4.1.3. Default value

Blank

5.4.1.4. Remarks

Separate entries by commas.
The values must be installed locally.
You must install the data store on a shared or dedicated server before installing other services.
You can only install services standalone, without installing the database simultaneously, if you have a Workload Balancing data store installed and specify it in the installation script using and for the database type. See Section 5.4.5, “DBNAME” and Section 5.4.4, “DATABASESERVER” for more information.

5.4.3. CERTNAMEPICKED

5.4.3.1. Definition

Specifies the subject name when you use Setup to create a self-signed SSL/TLS certificate. Alternatively, this specifies an existing certificate.

5.4.3.2. Possible values

cn. Use to specify the subject name of certificate to use or create.

5.4.3.3. Example

cn=wlb-kirkwood, where wlb-kirkwood is the name you are specifying as the name of the certificate to create or the certificate you want to select.

5.4.3.4. Default value

Specifies the database, and its instance name, where you want to install the data store. You can also use this property to specify an existing database that you want to use or upgrade.

5.4.3.5. Remarks

You must specify this parameter with the CERT_CHOICE parameter. See Section 5.4.2, “CERT_CHOICE” for more information.

5.4.4. DATABASESERVER

5.4.4.1. Definition

5.4.4.2. Possible values

If you specified an instance name when you installed SQL Server or SQL Express, append the server name with \yourinstancename. If you installed SQL Express without specifying an instance name, append the server name with \sqlexpress.

Note

5.4.4.3. Default value

Local

5.4.4.4. Example

DATABASESERVER="WLB-DB-SERVER\SQLEXPRESS", where WLB-DB-SERVER is the name of your database server and SQLEXPRESS is the name of the database instance.

5.4.4.5. Remarks

Required property for all installations.
Whether installing a database or connecting to an existing data store, you must specify this property with DBNAME.
Even if you are specifying a database on the same computer as you are performing Setup, you still must define the name of the database.
When you specify DATABASESERVER, in some circumstances, you must specify also Section 5.4.16, “WINDOWS_AUTH” and its accompanying properties.

5.4.5. DBNAME

5.4.5.1. Definition

The name of the Workload Balancing database that Setup will create or upgrade during installation.

5.4.5.2. Possible values

Specifies the user name for the Windows or SQL Server account you are using for database authentication during Setup.

5.4.5.3. Default value

WorkloadBalancing

5.4.5.4. Remarks

Required property for all installations. You must set a value for this property.
Whether connecting to or installing a data store, you must specify this property with DATABASESERVER.
Even if you are specifying a database on the same computer as you are performing Setup, you still must define the name of the database.
Localhost is not a valid value.

5.4.6. DBUSERNAME

5.4.6.1. Definition

5.4.6.2. Possible values

Specifies the password for the Windows or SQL Server account you are using for database authentication during Setup.

5.4.6.3. Default value

Blank

5.4.6.4. Remarks

This property is used with WINDOWS_AUTH (see Section 5.4.16, “WINDOWS_AUTH”) and DBPASSWORD (see Section 5.4.7, “DBPASSWORD”.)
Because you specify the server name and instance using Section 5.4.4, “DATABASESERVER”, do not qualify the user name.

5.4.7. DBPASSWORD

5.4.7.1. Definition

5.4.7.2. Possible values

5.4.7.3. Default value

Set this value to export an SSL/TLS certificate from the server on which you are installing Workload Balancing. Exporting the certificate lets you import it into the certificate stores of computers running XenServer.

5.4.7.4. Remarks

Use this property with the parameters documented in Section 5.4.16, “WINDOWS_AUTH” and Section 5.4.6, “DBUSERNAME”.

5.4.8. EXPORTCERT

5.4.8.1. Definition

5.4.8.2. Possible values

0. Does not exports the certificate.
1. Exports the certificate and saves it to the location of your choice with the file name you specify using EXPORTCERT_FQFN.

5.4.8.3. Default value

5.4.8.4. Remarks

Use with Section 5.4.9, “EXPORTCERT_FQFN”, which specifies the file name and path.
Setup does not require this property to run successfully. (That is, you do not have to export the certificate.)
This property lets you export self-signed certificates that you create during Setup as well as certificates that you created using a Trusted Authority.

5.4.9. EXPORTCERT_FQFN

5.4.9.1. Definition

Set to specify the path (location) and the file name you want Setup to use when exporting the certificate.

5.4.9.2. Possible values

The fully qualified path and file name to which to export the certificate. For example, C:\Certificates\WLBCert.cer.

5.4.9.3. Default value

Use this property with the parameter documented in Section 5.4.8, “EXPORTCERT”.

5.4.9.4. Remarks

5.4.10. HTTPS_PORT

5.4.10.1. Definition

Use this property to change the default port over which Workload Balancing (the Web Service Host service) communicates with XenServer.

Specify this property when you are running Setup on the computer that will host the Web Service Host service. This may be either the Workload Balancing computer, in a one-server deployment, or the computer hosting the services.

5.4.10.2. Possible values

Installation directory, where Installation directory is the location where the Workload Balancing software is installed.

5.4.10.3. Default value

8012

5.4.10.4. Remarks

If you set a value other than the default for this property, you must also change the value of this port in XenServer, which you can do with the Configure Workload Balancing wizard. The port number value specified during Setup and in the Configure Workload Balancing wizard must match.

5.4.11. INSTALLDIR

5.4.11.1. Definition

5.4.11.2. Possible values

User configurable

5.4.11.3. Default value

C:\Program Files\Citrix

5.4.12. PREREQUISITES_PASSED

5.4.12.1. Definition

You must set this property for Setup to continue. When enabled (PREREQUISITES_PASSED = 1), Setup skips checking preinstallation requirements, such as memory or operating system configurations, and lets you perform a command-line installation of the server.

5.4.12.2. Possible values

1. Indicates for Setup to not check for preinstallation requirements on the computer on which you are running Setup. You must set this property to 1 or Setup fails.

5.4.12.3. Default value

5.4.12.4. Remarks

This is a required value.

5.4.13. RECOVERYMODEL

5.4.13.1. Definition

Specifies the SQL Server database recovery model.

5.4.13.2. Possible values

SIMPLE. Specifies the SQL Server Simple Recovery model. Lets you recover the database from the end of any backup. Requires the least administration and consumes the lowest amount of disk space.
FULL. Specifies the Full Recovery model. Lets you recover the database from any point in time. However, this model uses consumes the largest amount of disk space for its logs.
BULK_LOGGED. Specifies the Bulk-Logged Recovery model. Lets you recover the database from the end of any backup. This model consumes less logging space than the Full Recovery model. However, this model provides more protection for data than the Simple Recovery model.

5.4.13.3. Default value

SIMPLE

5.4.13.4. Remarks

For more information about SQL Server recovery models, see the Microsoft's MSDN Web site and search for "Selecting a Recovery Model."

5.4.14. USERORGROUPACCOUNT

5.4.14.1. Definition

Specifies the account or group name that corresponds with the account XenServer will use when it connects to Workload Balancing. Specifying the name lets Workload Balancing recognize the connection.

5.4.14.2. Possible values

User name. Specify the name of the account you created for XenServer (for example, workloadbalancing_user).
Group name. Specify the group name for the account you created. Specifying a group name lets more than one person in your organization log on to Workload Balancing with their own credentials. (Otherwise, you will have to provide all users with the same set of credentials to use for Workload Balancing.)

5.4.14.3. Default value

Lets you select the authentication mode, either Windows or SQL Server, when connecting to the database server during Setup. For more information about database authentication during Setup, see SQL Server Database Authentication Requirements.

5.4.14.4. Remarks

This is a required parameter. You must use this parameter with Section 5.4.15, “WEBSERVICE_USER_CB ”.
To specify this parameter, you must create an account on the Workload Balancing server before running Setup. For more information, see Section 5.5.4, “Authorization for Workload Balancing ”.
This property does not require specifying another property for the password. You do not specify the password until you configure Workload Balancing.

5.4.16. WINDOWS_AUTH

5.4.16.1. Definition

5.4.16.3. Default value

5.4.16.4. Remarks

If you are logged into the server on which you are installing Workload Balancing with Windows credentials that have an account on the database server, you do not need to set this property.
If you specify WINDOWS_AUTH, you must also specify DBPASSWORD if you want to specify an account other than the one you are logged onto the server on which you are running Setup.
The account you specify must be a login on the SQL Server database with sysadmin privileges.

5.5. Initializing and Configuring Workload Balancing

Following Workload Balancing Setup, you must configure and enable (that is, initialize) Workload Balancing on each resource pool you want to monitor before Workload Balancing can gather data for that pool.

Before initializing Workload Balancing, configure your antivirus software to exclude Workload Balancing folders, as described in Section 5.5.5, “Configuring Antivirus Software”.

After the initial configuration, the Initialize button on the WLB tab changes to a Disable button. This is because after initialization you cannot modify the Workload Balancing server a resource pool uses without disabling Workload Balancing on that pool and then reconfiguring it. For information, see Section 5.10.2, “Reconfiguring a Resource Pool to Use Another WLB Server”.

Important

Following initial configuration, Citrix strongly recommends you evaluate your performance thresholds as described in Section 5.9.3.1, “Evaluating the Effectiveness of Your Optimization Thresholds”. It is critical to set Workload Balancing to the correct thresholds for your environment or its recommendations might not be appropriate.

You can use the Configure Workload Balancing wizard in XenCenter or the XE commands to initialize Workload Balancing or modify the configuration settings.

5.5.1. Initialization Overview

Initial configuration requires that you:

Specify the Workload Balancing server you want the resource pool to use and its port number.
Specify the credentials for communications, including the credentials:
- XenServer will use to connect to the Workload Balancing server
- Workload Balancing will use to connect to XenServer
For more information, see Section 5.5.4, “Authorization for Workload Balancing ”
Change the optimization mode, if desired, from Maximum Performance, the default setting, to Maximize Density. For information about the placement strategies, see Section 5.5.6, “Changing the Placement Strategy”.
Modify performance thresholds, if desired. You can modify the default utilization values and the critical thresholds for resources. For information about the performance thresholds, see Section 5.5.7, “Changing the Performance Thresholds and Metric Weighting”.
Modify metric weighting, if desired. You can modify the importance Workload Balancing assigns to metrics when it evaluates resource usage. For information about the performance thresholds, see Section 5.5.7.2, “Metric Weighting Factors”.

5.5.2. To initialize Workload Balancing

Use this procedure to enable and perform the initial configuration of Workload Balancing for a resource pool.

Before the Workload Balancing feature can begin collecting performance data, the XenServers you want to balance must be part of a resource pool. To complete this wizard, you need the:

IP address (or NetBIOS name) and (optionally) port of the Workload Balancing server
Credentials for the resource pool you want Workload Balancing to monitor
Credentials for the account you created on the Workload Balancing server

In the Resources pane of XenCenter, select XenCenter > <your-resource-pool>.
In the Properties pane, click the WLB tab.
In the WLB tab, click Initialize WLB.
In the Configure Workload Balancing wizard, click Next.
In the Server Credentials page, enter the following:
In the Basic Configuration page, do the following:

Do one of the following:

If you...	then...
want to modify advanced settings for thresholds and change the priority given to specific resources	click Next and continue with this procedure.
do not want to configure additional settings	click Finish.

In Critical Thresholds page, accept or enter a new value in the Critical Thresholds boxes.Workload Balancing uses these thresholds when making virtual-machine placement and pool-optimization recommendations. Workload Balancing strives to keep resource utilization on a host below the critical values set. For information about adjusting these thresholds, see Critical Thresholds.
In Metric Weighting page, if desired, adjust the sliders beside the individual resources. Moving the slider towards Less Important indicates that ensuring virtual machines always have the highest amount of this resource available is not as vital on this resource pool. For information about adjusting metric weighting, see Metric Weighting Factors.
Click Finish.

5.5.3. To edit the Workload Balancing configuration for a pool

After initialization, you can use this procedure to edit the Workload Balancing performance thresholds and placement strategies for a specific resource pool.

In the Resources pane of XenCenter, select XenCenter > <your-resource-pool> .
In the Properties pane, click the WLB tab.
In the WLB tab, click Configure WLB.
In the Configure Workload Balancing wizard, click Next.
In the Basic Configuration page, do the following:

Do one of the following:

If you...	then...
want to modify advanced settings for thresholds and change the priority given to specific resources	click Next and continue with this procedure.
do not want to configure additional settings	click Finish.

In Critical Thresholds page, accept or enter a new value in the Critical Thresholds boxes.Workload Balancing uses these thresholds when making virtual-machine placement and pool-optimization recommendations. Workload Balancing strives to keep resource utilization on a host below the critical values set. For information about adjusting these thresholds, see Section 5.5.7.1, “Critical Thresholds”.
In Metric Weighting page, if desired, adjust the sliders beside the individual resources. Moving the slider towards Less Important indicates that ensuring virtual machines always have the highest amount of this resource available is not as vital on this resource pool. For information about adjusting metric weighting, see Section 5.5.7.2, “Metric Weighting Factors”.
Click Finish.

5.5.4. Authorization for Workload Balancing

When you are configuring a XenServer resource pool to use Workload Balancing, you must specify credentials for two accounts:

User Account for Workload Balancing to connect to XenServer. Workload Balancing uses a XenServer user account to connect to XenServer. You provide Workload Balancing with this account's credentials when you run the Configure Workload Balancing wizard. Typically, you specify the credentials for the pool (that is, the pool master's credentials).
User Account for XenServer to Connect to Workload Balancing. XenServer communicates with the Web Service Host using the user account you created before Setup. During Workload Balancing Setup, you specified the authorization type (a single user or group) and the user or group with permissions to make requests from the Web Service Host service. During configuration, you must provide XenServer with this account's credentials when you run the Configure Workload Balancing wizard.

5.5.5. Configuring Antivirus Software

By default, most antivirus programs are configured to scan all files on the hard disk. If an antivirus program scans the frequently active Workload Balancing database, it impedes or slows down the normal operation of Workload Balancing. Consequently, you must configure antivirus software running on your Workload Balancing servers to exclude specific processes and files. Citrix recommends configuring your antivirus software to exclude these folders before you initialize Workload Balancing and begin collecting data.

To configure antivirus software on the servers running Workload Balancing components:

Exclude the following folder, which contains the Workload Balancing log:On Windows XP and Windows Server 2003: %Documents and Settings%\All Users\Application Data\Citrix\Workload Balancing\Data\Logfile.log On Windows Vista and Windows Server 2008: %Program Data%\Citrix\Workload Balancing\Data\Logfile.log.
Exclude the SQL Server database folder. For example:On SQL Server: %Program Files%\Microsoft SQL Server\MSSQL\Data\On SQL Server Express: %Program Files%\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\Data\These paths may vary according to your operating system and SQL Server version.

Note

These paths and file names are for 32-bit default installations. Use the values that apply to your installation. For example, paths for 64-bit edition files might be in the %Program Files (x86)% folder.

5.5.6. Changing the Placement Strategy

The Workload Balancing feature bases its optimization recommendations on whether you choose Maximize Performance or Maximize Density as your optimization mode.

5.5.6.1. Maximize Performance

(Default.) Workload Balancing attempts to spread workload evenly across all physical hosts in a resource pool. The goal is to minimize CPU, memory, and network pressure for all hosts. When Maximize Performance is your placement strategy, Workload Balancing recommends optimization when a virtual machine reaches the High threshold.

5.5.6.2. Maximize Density

Workload Balancing attempts to fit as many virtual machines as possible onto a physical host. The goal is to minimize the number of physical hosts that must be online.

When you select Maximize Density as your placement strategy, you can specify rules similar to the ones in Maximize Performance. However, Workload Balancing uses these rules to determine how it can pack virtual machines onto a host. When Maximize Density is your placement strategy, Workload Balancing recommends optimization when a virtual machine reaches the Critical threshold.

5.5.7. Changing the Performance Thresholds and Metric Weighting

Workload Balancing evaluates CPU, Memory, Network Read, Network Write, Disk Read, and Disk Write utilization for physical hosts in a resource pool.

Workload Balancing determines whether to recommend relocating a workload and whether a physical host is suitable for a virtual-machine workload by evaluating:

Whether a resource's critical threshold is met on the physical host
(If the critical threshold is met) the importance assigned to a resource

Note

To prevent data from appearing artificially high, Workload Balancing evaluates the daily averages for a resource and smooths utilization spikes.

5.5.7.1. Critical Thresholds

When evaluating utilization, Workload Balancing compares its daily average to four thresholds: low, medium, high, and critical. After you specify (or accept the default) critical threshold, Workload Balancing sets the other thresholds relative to the critical threshold on a pool.

5.5.7.2. Metric Weighting Factors

Workload Balancing lets you indicate if a resource's utilization is significant enough to warrant or prevent relocating a workload. For example, if you set memory as a Less Important factor in placement recommendations, Workload Balancing may still recommend placing virtual machines you are relocating on a server with high-memory utilization.

The effect of the weighting varies according to the placement strategy you selected. For example, if you selected Maximum Performance and you set Network Writes towards Less Important, if the Network Writes on that server exceed the critical threshold you set, Workload Balancing still makes a recommendation to place a virtual machine's workload on a server but does so with the goal of ensuring performance for the other resources.

If you selected Maximum Density as your placement recommendation and you specify Network Writes as Less Important, Workload Balancing will still recommend placing workloads on that host if the Network Writes exceed the critical threshold you set. However, the workloads are placed in the densest possible way.

5.5.7.3. Editing Resource Settings

For each resource pool, you can edit a resource's critical performance threshold and modify the importance or "weight" the Workload Balancing gives to a resource.

Citrix recommends using most of the defaults in the Configure Workload Balancing wizard initially. However, you might need to change the network and disk thresholds to align them with the hardware in your environment.

After Workload Balancing is enabled for a while, Citrix recommends evaluating your performance thresholds and determining if you need to edit them. For example, consider if you are:

Getting optimization recommendation when they are not yet required. If this is the case, try adjusting the thresholds until Workload Balancing begins providing suitable optimization recommendations.
Not getting recommendations when you think your network has insufficient bandwidth. If this is the case, try lowering the network critical thresholds until Workload Balancing begins providing optimization recommendations.

Before you edit your thresholds, you might find it useful to generate a host health history report for each physical host in the pool. See Section 5.9.6.1, “Host Health History” for more information.

5.6. Accepting Optimization Recommendations

Workload Balancing provides recommendations about ways you can move virtual machines to optimize your environment. Optimization recommendations appear in the WLB tab in XenCenter. Optimization recommendations are based on the:

Placement strategy you select (that is, the placement optimization mode), as described in Section 5.5.6, “Changing the Placement Strategy”
Performance metrics for resources such as a physical host's CPU, memory, network, and disk utilization

The optimization recommendations display the name of the virtual machine that Workload Balancing recommends relocating, the host it currently resides on, and the host Workload Balancing recommends as the machine's new location. The optimization recommendations also display the reason Workload Balancing recommends moving the virtual machine (for example, "CPU" to improve CPU utilization).

After you accept an optimization recommendation, XenServer relocates all virtual machines listed as recommended for optimization.

Tip

You can find out the optimization mode for a resource pool by selecting the pool in XenCenter and checking the Configuration section of the WLB tab.

5.7. Choosing an Optimal Server for VM Initial Placement, Migrate, and Resume

When Workload Balancing is enabled and you restart a virtual machine that is offline, XenCenter provides recommendations to help you determine the optimal physical host in the resource pool on which to start the virtual machine. Workload Balancing makes these placement recommendations by using performance metrics it previously gathered for that virtual machine and the physical hosts in the resource pool. Likewise, when Workload Balancing is enabled, if you migrate a virtual machine to another host, XenCenter recommends servers to which you can move that host. This Workload Balancing enhancement is also available for the Initial (Start On) Placement and Resume features

When you use these features with Workload Balancing enabled, host recommendations appear as star ratings beside the name of the physical host. Five empty stars indicates the lowest-rated (least optimal) server. When it is not possible to start or move a virtual machine to a host, an (X) appears beside the host name with the reason.

5.7.1. To start a virtual machine on the optimal server

In the Resources pane of XenCenter, select the virtual machine you want to start.
From the VM menu, select Start on Server and then select one of the following:
- Optimal Server. The optimal server is the physical host that is best suited to the resource demands of the virtual machine you are starting. Workload Balancing determines the optimal server based on its historical records of performance metrics and your placement strategy. The optimal server is the server with the most stars.
- One of the servers with star ratings listed under the Optimal Server command. Five stars indicates the most-recommended (optimal) server and and five empty stars indicates the least-recommended server.

5.7.1.1. To resume a virtual machine on the optimal server

In the Resources pane of XenCenter, select the suspended virtual machine you want to resume.
From the VM menu, select Resume on Server and then select one of the following:
- Optimal Server. The optimal server is the physical host that is best suited to the resource demands of the virtual machine you are starting. Workload Balancing determines the optimal server based on its historical records of performance metrics and your placement strategy. The optimal server is the server with the most stars.
- One of the servers with star ratings listed under the Optimal Server command. Five stars indicates the most-recommended (optimal) server and five empty stars indicates the least-recommended server.

5.8. Entering Maintenance Mode with Workload Balancing Enabled

When Workload Balancing is enabled, if you take a physical host offline for maintenance (that is, suspend a server by entering Maintenance Mode), XenServer automatically migrates the virtual machines running on that host to their optimal servers when available. XenServer migrates them based on Workload Balancing recommendations (performance data, your placement strategy, and performance thresholds).

If an optimal server is not available, the words Click here to suspend the VM appear in the Enter Maintenance Mode dialog box. In this case, Workload Balancing does not recommend a placement because no host has sufficient resources to run this virtual machine. You can either suspend this virtual machine or exit Maintenance Mode and suspend a virtual machine on another host in the same pool. Then, if you reenter the Enter Maintenance Modedialog box, Workload Balancing might be able to list a host that is a suitable candidate for migration.

Note

When you take a server offline for maintenance and Workload Balancing is enabled, the words "Workload Balancing" appear in the upper-right corner of the Enter Maintenance Mode dialog box.

5.8.1. To enter maintenance mode with Workload Balancing enabled

In the Resources pane of XenCenter, select the physical host that you want to take offline. From the Server menu, select Enter Maintenance Mode.
In the Enter Maintenance Mode dialog box, click Enter maintenance mode. The virtual machines running on the server are automatically migrated to the optimal host based on Workload Balancing's performance data, your placement strategy, and performance thresholds.

To take the server out of maintenance mode, right-click the server and select Exit Maintenance Mode. When you remove a server from maintenance mode, XenServer automatically restores that server's original virtual machines to that server.

5.9. Working with Workload Balancing Reports

This topic provides general information about Workload Balancing historical reports and an overview of where to find additional information about these reports.

To generate a Workload Balancing report, you must have installed the Workload Balancing component, registered at least one resource pool with Workload Balancing, and configured Workload Balancing on at least one resource pool.

5.9.1. Introduction

Workload Balancing provides reporting on three types of objects: physical hosts, resource pools, and virtual machines. At a high level, Workload Balancing provides two types of reports:

Historical reports that display information by date
"Roll up" style reports

Workload Balancing provides some reports for auditing purposes, so you can determine, for example, the number of times a virtual machine moved.

5.9.2. Types of Workload Balancing Reports

Workload Balancing includes the following reports:

Section 5.9.6.1, “Host Health History” . Similar to Pool Health History but filtered by a specific host.
Section 5.9.6.2, “Optimization Performance History” . Shows resource usage before and after executing optimization recommendations.
Section 5.9.6.3, “Pool Health”. Shows aggregated resource usage for a pool. Helps you evaluate the effectiveness of your optimization thresholds.
Section 5.9.6.4, “Pool Health History” . Displays resource usage for a pool over time. Helps you evaluate the effectiveness of your optimization thresholds.
Section 5.9.6.5, “Virtual Machine Motion History” . Provides information about how many times virtual machines moved on a resource pool, including the name of the virtual machine that moved, number of times it moved, and physical hosts affected.
Section 5.9.6.6, “Virtual Machine Performance History” . Displays key performance metrics for all virtual machines that operated on a host during the specified timeframe.

5.9.3. Using Workload Balancing Reports for Tasks

The Workload Balancing reports can help you perform capacity planning, determine virtual server health, and evaluate the effectiveness of your configured threshold levels.

5.9.3.1. Evaluating the Effectiveness of Your Optimization Thresholds

You can use the Pool Health report to evaluate the effectiveness of your optimization thresholds. Workload Balancer provides default threshold settings. However, you might need to adjust these defaults for them to provide value in your environment. If you don't have the optimization thresholds adjusted to the correct level for your environment, Workload Balancing recommendations might not be appropriate for your environment.

5.9.4. Creating Workload Balancing Reports

This topic explains how to generate, navigate, print, and export Workload Balancing reports.

5.9.4.2. To navigate in a Workload Balancing Report

After generating a report, you can use the toolbar buttons in the report to navigate and perform certain tasks. To display the name of a toolbar button, hold your mouse over toolbar icon.

Table 5.1. Report Toolbar Buttons

Document Map. Lets you display a document map that helps you navigate through long reports.

Page Forward/Back. Lets you move one page ahead or back in the report.

Back to Parent Report. Lets you return to the parent report when working with drill-through reports.

Stop Rendering. Cancels the report generation.

Refresh. Lets you refresh the report display.

Print. Lets you print a report and specify general printing options, such as the printer, the number of pages, and the number of copies.

Print Layout. Lets you display a preview of the report before you print it.

Page Setup. Lets you specify printing options such as the paper size, page orientation, and margins.

Export. Lets you export the report as an Acrobat (.PDF) file or as an Excel file with a .XLS extension.

Find. Lets you search for a word in a report, such as the name of a virtual machine.

5.9.5. Generating Workload Balancing Reports

The Workload Reports window lets you generate reports for physical hosts, resource pools, and virtual machines.

5.9.5.1. Report Generation Features

To generate a report, select a report type, the date range, the host (if applicable), and click Run Report. For more detail, see Section 5.9.4, “Creating Workload Balancing Reports”.

5.9.5.2. Types of Workload Balancing Reports

Workload Balancing includes the following reports:

Section 5.9.6.1, “Host Health History” . Similar to Pool Health History but filtered by a specific host.
Section 5.9.6.2, “Optimization Performance History” . Shows resource usage before and after executing optimization recommendations.
Section 5.9.6.3, “Pool Health”. Shows aggregated resource usage for a pool. Helps you evaluate the effectiveness of your optimization thresholds.
Section 5.9.6.4, “Pool Health History”. Displays resource usage for a pool over time. Helps you evaluate the effectiveness of your optimization thresholds.
Section 5.9.6.5, “Virtual Machine Motion History” . Provides information about how many times virtual machines moved on a resource pool, including the name of the virtual machine that moved, number of times it moved, and physical hosts affected.
Section 5.9.6.6, “Virtual Machine Performance History” . Displays key performance metrics for all virtual machines that operated on a host during the specified timeframe.

5.9.5.3. Toolbar Buttons

The following toolbar buttons in the Workload Reports window become available after you generate a report. To display the name of a toolbar button, hold your mouse over toolbar icon.

Table 5.2. Report Toolbar Buttons

Document Map. Lets you display a document map that helps you navigate through long reports.

Page Forward/Back. Lets you move one page ahead or back in the report.

Back to Parent Report. Lets you return to the parent report when working with drill-through reports.

Stop Rendering. Cancels the report generation.

Refresh. Lets you refresh the report display.

Print. Lets you print a report and specify general printing options, such as the printer, the number of pages, and the number of copies.

Print Layout. Lets you display a preview of the report before you print it.

Page Setup. Lets you specify printing options such as the paper size, page orientation, and margins.

Export. Lets you export the report as an Acrobat (.PDF) file or as an Excel file with a .XLS extension.

Find. Lets you search for a word in a report, such as the name of a virtual machine.

5.9.6. Workload Balancing Report Glossary

This topic provides information about the following Workload Balancing reports.

5.9.6.1. Host Health History

This report displays the performance of resources (CPU, memory, network reads, and network writes) on specific host in relation to threshold values.

The colored lines (red, green, yellow) represent your threshold values. You can use this report with the Pool Health report for a host to determine how a particular host's performance might be affecting overall pool health. When you are editing the performance thresholds, you can use this report for insight into host performance.

You can display resource utilization as a daily or hourly average. The hourly average lets you see the busiest hours of the day, averaged, for the time period.

To view report data grouped by hour, expand + Click to view report data grouped by house for the time period under the Host Health History title bar.

Workload Balancing displays the average for each hour for the time period you set. The data point is based on a utilization average for that hour for all days in the time period. For example, in a report for May1, 2009 to May 15, 2009, the Average CPU Usage data point represents the resource utilization of all fifteen days at 12:00 hours combined together as an average. That is, if CPU utilization was 82% at 12PM on May 1st, 88% at 12PM on May 2nd, and 75% on all other days, the average displayed for 12PM is 76.3%.

Note

Workload Balancing smooths spikes and peaks so data does not appear artificially high.

5.9.6.2. Optimization Performance History

The optimization performance report displays optimization events (that is, when you optimized a resource pool) against that pool's average resource usage. Specifically, it displays resource usage for CPU, memory, network reads, and network writes.

The dotted line represents the average usage across the pool over the period of days you select. A blue bar indicates the day on which you optimized the pool.

This report can help you determine if Workload Balancing is working successfully in your environment. You can use this report to see what led up to optimization events (that is, the resource usage before Workload Balancing recommended optimizing).

This report displays average resource usage for the day; it does not display the peak utilization, such as when the system is stressed. You can also use this report to see how a resource pool is performing if Workload Balancing is not making optimization recommendations.

In general, resource usage should decline or be steady after an optimization event. If you do not see improved resource usage after optimization, consider readjusting threshold values. Also, consider whether or not the resource pool has too many virtual machines and whether or not new virtual machines were added or removed during the timeframe you specified.

5.9.6.3. Pool Health

The pool health report displays the percentage of time a resource pool and its hosts spent in four different threshold ranges: Critical, High, Medium, and Low. You can use the Pool Health report to evaluate the effectiveness of your performance thresholds.

A few points about interpreting this report:

Resource utilization in the Average Medium Threshold (blue) is the optimum resource utilization regardless of the placement strategy you selected. Likewise, the blue section on the pie chart indicates the amount of time that host used resources optimally.
Resource utilization in the Average Low Threshold Percent (green) is not necessarily positive. Whether Low resource utilization is positive depends on your placement strategy. For example, if your placement strategy is Maximum Density and most of the time your resource usage was green, Workload Balancing might not be fitting the maximum number of virtual machines possible on that host or pool. If this is the case, you should adjust your performance threshold values until the majority of your resource utilization falls into the Average Medium (blue) threshold range.
Resource utilization in the Average Critical Threshold Percent (red) indicates the amount of time average resource utilization met or exceeded the Critical threshold value.

If you double-click on a pie chart for a host's resource usage, XenCenter displays the Host Health History report for that resource (for example, CPU) on that host. Clicking the Back to Parent Report toolbar button returns you to the Pool Health history report.

If you find the majority of your report results are not in the Average Medium Threshold range, you probably need to adjust the Critical threshold for this pool. While Workload Balancing provides default threshold settings, these defaults are not effective in all environments. If you do not have the thresholds adjusted to the correct level for your environment, Workload Balancing's optimization and placement recommendations might not be appropriate. For more information, see Section 5.5.7, “Changing the Performance Thresholds and Metric Weighting”.

Note

The High, Medium, and Low threshold ranges are based on the Critical threshold value you set when you initialized Workload Balancing.

5.9.6.4. Pool Health History

This report provides a line graph of resource utilization on all physical hosts in a pool over time. It lets you see the trend of resource utilization - if it tends to be increasing in relation to your thresholds (Critical, High, Medium, and Low). You can evaluate the effectiveness of your performance thresholds by monitoring trends of the data points in this report.

Workload Balancing extrapolates the threshold ranges from the values you set for the Critical thresholds when you initialized Workload Balancing. Although similar to the Pool Health report, the Pool Health History report displays the average utilization for a resource on a specific date rather than the amount of time overall the resource spent in a threshold.

With the exception of the Average Free Memory graph, the data points should never average above the Critical threshold line (red). For the Average Free Memory graph, the data points should never average below the Critical threshold line (which is at the bottom of the graph). Because this graph displays free memory, the Critical threshold is a low value, unlike the other resources.

A few points about interpreting this report:

When the Average Usage line in the chart approaches the Average Medium Threshold (blue) line, it indicates the pool's resource utilization is optimum regardless of the placement strategy configured.
Resource utilization approaching the Average Low Threshold (green) is not necessarily positive. Whether Low resource utilization is positive depends on your placement strategy. For example, if your placement strategy is Maximum Density and most days the Average Usage line is at or below the green line, Workload Balancing might not be placing virtual machines as densely as possible on that pool. If this is the case, you should adjust the pool's Critical threshold values until the majority of its resource utilization falls into the Average Medium (blue) threshold range.
When the Average Usage line intersects with the Average Critical Threshold Percent (red), this indicates the days when the average resource utilization met or exceeded the Critical threshold value for that resource.

If you find the data points in the majority of your graphs are not in the Average Medium Threshold range, but you are satisfied with the performance of this pool, you might need to adjust the Critical threshold for this pool. For more information, see Section 5.5.7, “Changing the Performance Thresholds and Metric Weighting”.

5.9.6.5. Virtual Machine Motion History

This line graph displays the number of times virtual machines moved on a resource pool over a period of time. It indicates if a move resulted from an optimization recommendation and to which host the virtual machine moved. This report also indicates the reason for the optimization. You can use this report to audit the number of moves on a pool.

Some points about interpreting this report:

The numbers on the left side of the chart correspond with the number of moves possible, which is based on how many virtual machines are in a resource pool.
You can look at details of the moves on a specific date by expanding the + sign in the Date section of the report.

5.9.6.6. Virtual Machine Performance History

This report displays performance data for each virtual machine on a specific host for a time period you specify. Workload Balancing bases the performance data on the amount of virtual resources allocated for the virtual machine. For example, if the Average CPU Usage for your virtual machine is 67%, this means that your virtual machine was using, on average, 67% of its virtual CPU for the period you specified.

The initial view of the report displays an average value for resource utilization over the period you specified.

Expanding the + sign displays line graphs for individual resources. You can use these graphs to see trends in resource utilization over time.

This report displays data for CPU Usage, Free Memory, Network Reads/Writes, and Disk Reads/Writes.

5.10. Administering Workload Balancing

Some administrative tasks you may want to perform on Workload Balancing include disabling Workload Balancing on a pool, pointing a pool to use a different Workload Balancing server, and uninstalling Workload Balancing.

5.10.1. Disabling Workload Balancing on a Resource Pool

You can disable Workload Balancing for a resource pool, either temporarily or permanently:

Temporarily. Disabling Workload Balancing temporarily stops XenCenter from displaying recommendations for the specified resource pool. When you disable Workload Balancing temporarily, data collection stops for that resource pool.
Permanently. Disabling Workload Balancing permanently deletes information about the specified resource pool from the data store and stops data collection for that pool.

To disable Workload Balancing on a resource pool

In the Resource pane of XenCenter, select the resource pool for which you want to disable Workload Balancing.
In the WLB tab, click Disable WLB. A dialog box appears asking if you want to disable Workload Balancing for the pool.
Click Yes to disable Workload Balancing for the pool. Important: If you want to disable Workload Balancing permanently for this resource pool, click the Remove all resource pool information from the Workload Balancing Server check box.

XenServer disables Workload Balancing for the resource pool, either temporarily or permanently depending on your selections.

If you disabled Workload Balancing temporarily on a resource pool, to reenable Workload Balancing, click Enable WLB in the WLB tab.
If you disabled Workload Balancing permanently on a resource pool, to reenable it, you must reinitialize it. For information, see To initialize Workload Balancing.

5.10.2. Reconfiguring a Resource Pool to Use Another WLB Server

You can reconfigure a resource pool to use a different Workload Balancing server. However, to prevent old data collectors from remaining inadvertently configured and running against a pool, you must disable Workload Balancing permanently for that resource pool before pointing the pool to another data collector. After disabling Workload Balancing, you can re-initialize the pool and specify the name of the new Workload Balancing server.

To use a different Workload Balancing server

On the resource pool you want to point to a different Workload Balancing server, disable Workload Balancing permanently. You do this by deleting its information for the resource pool from the data store and stop collecting data. For instructions, see Section 5.10.1, “Disabling Workload Balancing on a Resource Pool”.
In the Resource pane of XenCenter, select the resource pool for which you want to reenable Workload Balancing.
In the WLB tab, click Initialize WLB. The Configure Workload Balancing wizard appears.
Reinitialize the resource pool and specify the new server's credentials in the Configure Workload Balancing wizard. You must provide the same information as you do when you initially configure a resource pool for use with Workload Balancing. For information, see Section 5.5.2, “To initialize Workload Balancing”.

5.10.3. Uninstalling Workload Balancing

Citrix recommends uninstalling Workload Balancing from the Control Panel in Windows.

When you uninstall Workload Balancing, only the Workload Balancing software is removed from the Workload Balancing server. The data store remains on the system running SQL Server. To remove a Workload Balancing data store, you must use the SQL Server Management Studio (SQL Server 2005 and SQL Server 2008).

If you want to uninstall both Workload Balancing and SQL Server from your computer, uninstall Workload Balancing first and then delete the database using the SQL Server Management Studio.

The data directory, usually located at %Documents and Settings%\All Users\Application Data\Citrix\Workload Balancing\Data, is not removed when you uninstall Workload Balancing. You can remove the contents of the data directory manually.

5.11. Troubleshooting Workload Balancing

While Workload Balancing usually runs smoothly, this series of topics provides guidance in case you encounter issues.

Here are a few tips for resolving general Workload Balancing issues:

5.11.1. General Troubleshooting Tips

5.11.2. Error Messages

Workload Balancing displays error messages in the Log tab in XenCenter, in the Windows Event log, and, in some cases, on screen as dialog boxes.

5.11.3. Issues Installing Workload Balancing

When troubleshooting installation issues, start by checking the installation log file.

The location of the installation varies depending on whether you installed Workload Balancing using the command-line installation or the Setup wizard. If you used the Setup wizard, the log is at %Documents and Settings%\username\Local Settings\Temp\msibootstrapper2CSM_MSI_Install.log (by default).

Tip

When troubleshooting installations using installations logs, the log file is overwritten each time you install. You might want to manually copy the installation logs to separate directory so that you can compare them.

For common installation and Msiexec errors, try searching the Citrix Knowledge Center and the Internet.

To verify that you installed Workload Balancing successfully, see Section 5.3.5.3.1, “To verify your Workload Balancing installation”.

5.11.5. Issues Starting Workload Balancing

If after installing and configuring Workload Balancing, you receive an error message that XenServer and Workload Balancing cannot connect to each other, you might have entered the incorrect credentials. To isolate this issue, try:

Verifying the credentials you entered in the Configure Workload Balancing wizard match the credentials:
- You created on the Workload Balancing server
- On XenServer
Verifying the IP address or NetBIOS name of the Workload Balancing server you entered in the Configure Workload Balancing wizard is correct.
Verifying the user or group name you entered during Setup matches the credentials you created on the Workload Balancing server. To check what user or group name you entered, open the install log (search for log.txt) and search for userorgroupaccount.

5.11.6. Workload Balancing Connection Errors

If you receive a connection error in the Workload Balancing Status line on the WLB tab, you might need to reconfigure Workload Balancing on that resource pool.

Click the Configure button on the WLB tab and reenter the server credentials.

Typical causes for this error include changing the server credentials or inadvertently deleting the Workload Balancing user account.

5.11.7. Issues Changing Workload Balancing Servers

If you change the Workload Balancing server a resource pool references without first deconfiguring Workload Balancing on the resource pool, both the old and new Workload Balancing server will monitor the pool.

To solve this problem, you can either uninstall the old Workload Balancing Server or manually stop the Workload Balancing services (analysis, data collector and Web service) so that it will no longer monitor the pool.

Citrix does not recommend using the pool-initialize-wlb XE command to deconfigure or change Workload Balancing servers.

Chapter 6. Backup and recovery

6.2. Full metadata backup and disaster recovery (DR)

6.1. Backups

6.2.1. DR and metadata backup overview
6.2.2. Backup and restore using xsconsole
6.2.3. Moving SRs between hosts and Pools
6.2.4. Using Portable SRs for Manual Multi-Site Disaster Recovery

6.3. VM Snapshots

6.3.1. Regular Snapshots
6.3.2. Quiesced Snapshots
6.3.3. Taking a VM snapshot
6.3.4. VM Rollback

6.4. Coping with machine failures

6.4.1. Member failures
6.4.2. Master failures
6.4.3. Pool failures
6.4.4. Coping with Failure due to Configuration Errors
6.4.5. Physical Machine failure

This chapter presents the functionality designed to give you the best chance to recover your XenServer from a catastrophic failure of hardware or software, from lightweight metadata backups to full VM backups and portable SRs.

6.1. Backups

Citrix recommends that you frequently perform as many of the following backup procedures as possible to recover from possible server and/or software failure.

To backup pool metadata

xe pool-dump-database file-name=<backup>

Run the command:
```
xe pool-restore-database file-name=<backup> dry-run=true
```
This command checks that the target machine has an appropriate number of appropriately named NICs, which is required for the backup to succeed.

To backup host configuration and software

xe host-backup host=<host> file-name=<hostbackup>

Note

Do not create the backup in the control domain.
This procedure may create a large backup file.
To complete a restore you have to reboot to the original install CD.
This data can only be restored to the original machine.

To backup a VM

Ensure that the VM to be backed up is offline.

This backup also backs up all of the VM's data. When importing a VM, you can specify the storage mechanism to use for the backed up data.

xe vm-export vm=<vm_uuid> filename=<backup>

Note

Warning

Because this process backs up all of the VM data, it can take some time to complete.

To backup VM metadata only

This section introduces the concept of Portable Storage Repositories (Portable SRs), and explains how they work and how to use them as part of a DR strategy.

xe vm-export vm=<vm_uuid> filename=<backup> --metadata

6.2. Full metadata backup and disaster recovery (DR)

6.2.1. DR and metadata backup overview

XenServer 5.5.0 introduces the concept of Portable SRs. Portable SRs contain all of the information necessary to recreate all the Virtual Machines (VMs) with Virtual Disk Images (VDIs) stored on the SR after re-attaching the SR to a different host or pool. Portable SRs can be used when regular maintenance or disaster recovery requires manually moving a SR between pools or standalone hosts.

Using portable SRs has similar constraints to XenMotion as both cases result in VMs being moved between hosts. To use portable SRs:

The source and destination hosts must have the same CPU type and networking configuration. The destination host must have a network of the same name as the one of the source host.
The SR media itself, such as a LUN for iSCSI and FibreChannel SRs, must be able to be moved, re-mapped, or replicated between the source and destination hosts
If using tiered storage, where a VM has VDIs on multiple SRs, all required SRs must be moved to the destination host or pool
Any configuration data required to connect the SR on the destination host or pool, such as the target IP address, target IQN, and LUN SCSI ID for iSCSI SRs, and the LUN SCSI ID for FibreChannel SRs, must be maintained manually
The backup metadata option must be configured for the desired SR

Note

When moving portable SRs between pools the source and destination pools are not required to have the same number of hosts. Moving portable SRs between pools and standalone hosts is also supported provided the above constraints are met.

Portable SRs work by creating a dedicated metadata VDI within the specified SR. The metadata VDI is used to store copies of the pool or host database as well as the metadata describing the configuration of each VM. As a result the SR becomes fully self-contained, or portable, allowing it to be detached from one host and attached to another as a new SR. Once the SR is attached a restore process is used to recreate all of the VMs on the SR from the metadata VDI. For disaster recovery the metadata backup can be scheduled to run regularly to ensure the metadata SR is current.

The metadata backup and restore feature works at the command-line level and the same functionality is also supported in xsconsole. It is not currently available through XenCenter.

6.2.2. Backup and restore using xsconsole

When a metadata backup is first taken, a special backup VDI is created on a SR. This VDI has an ext3 filesystem that stores the following versioned backups:

A full pool-database backup.
Individual VM metadata backups, partitioned by the SRs in which the VM has disks.
SR-level metadata which can be used to recreate the SR description when the storage is reattached.

In the menu-driven text console on the XenServer host, there are some menu items under the Backup, Update and Restore menu which provide more user-friendly interfaces to these scripts. The operations should only be performed on the pool master. You can use these menu items to perform 3 operations:

Schedule a regular metadata backup to the default pool SR, either daily, weekly or monthly. This will regularly rotate metadata backups and ensure that the latest metadata is present for that SR without any user intervention being required.
Trigger an immediate metadata backup to the SR of your choice. This will create a backup VDI if necessary, and attach it to the host and backup all the metadata to that SR. Use this option if you have made some changes which you want to see reflected in the backup immediately.
Perform a metadata restoration operation. This will prompt you to choose an SR to restore from, and then the option of restoring only VM records associated with that SR, or all the VM records found (potentially from other SRs which were present at the time of the backup). There is also a dry run option to see which VMs would be imported, but not actually perform the operation.

For automating this scripting, there are some commands in the control domain which provide an interface to metadata backup and restore at a lower level than the menu options:

xe-backup-metadata provides an interface to create the backup VDIs (with the -c flag), and also to attach the metadata backup and examine its contents.
xe-restore-metadata can be used to probe for a backup VDI on a newly attached SR, and also selectively reimport VM metadata to recreate the associations between VMs and their disks.

Full usage information for both scripts can be obtained by running them in the control domain using the -h flag. One particularly useful invocation mode is xe-backup-metadata -d which mounts the backup VDI into dom0, and drops into a sub-shell with the backup directory so it can be examined.

6.2.3. Moving SRs between hosts and Pools

The metadata backup and restore options can be run as scripts in the control domain or through the Backup, Restore, and Update menu option in the xsconsole. All other actions, such as detaching the SR from the source host and attaching it to the destination host, can be performed using XenCenter, the menu-based xsconsole, or the xe CLI. This example uses a combination of XenCenter and xsconsole.

To create and move a portable SR using the xsconsole and XenCenter

On the source host or pool, in xsconsole, select the Backup, Restore, and Update menu option, select the Backup Virtual Machine Metadata option, and then select the desired SR.
In XenCenter, select the source host or pool and shutdown all running VMs with VDIs on the SR to be moved.
In the tree view select the SR to be moved and select Storage > Detach Storage Repository. The Detach Storage Repository menu option will not be displayed if there are running VMs with VDIs on the selected SR. After being detached the SR will be displayed in a grayed-out state.
Warning
Do not complete this step unless you have created a backup VDI in step 1.
Select Storage > Forget Storage Repository to remove the SR record from the host or pool.
Select the destination host in the tree view and select Storage > New Storage Repository.
Create a new SR with the appropriate parameters required to reconnect the existing SR to the destination host. In the case of moving a SR between pools or hosts within a site the parameters may be identical to the source pool.
Every time a new SR is created the storage is checked to see if it contains an existing SR. If so, an option is presented allowing re-attachment of the existing SR. If this option is not displayed the parameters specified during SR creation are not correct.
Select Reattach.
Select the new SR in the tree view and then select the Storage tab to view the existing VDIs present on the SR.
In xsconsole on the destination host, select the Backup, Restore, and Update menu option, select the Restore Virtual Machine Metadata option, and select the newly re-attached SR.
The VDIs on the selected SR are inspected to find the metadata VDI. Once found, select the metadata backup you want to use.
Select the Only VMs on this SR option to restore the VMs.
Note
Use the All VM Metadata option when moving multiple SRs between hosts or pools, or when using tiered storage where VMs to be restored have VDIs on multiple SRs. When using this option ensure all required SRs have been reattached to the destination host prior running the restore.
The VMs are restored in the destination pool in a shutdown state and are available for use.

6.2.4. Using Portable SRs for Manual Multi-Site Disaster Recovery

The Portable SR feature can be used in combination with storage layer replication in order to simplify the process of creating and enabling a disaster recovery (DR) site. Using storage layer replication to mirror or replicate LUNs that comprise portable SRs between production and DR sites allows all required data to be automatically present in the DR site. The constraints that apply when moving portable SRs between hosts or pools within the same site also apply in the multi-site case, but the production and DR sites are not required to have the same number of hosts. This allows use of either dedicated DR facilities or non-dedicated DR sites that run other production workloads.

Using portable SRs with storage layer replication between sites to enable the DR site in case of disaster

Any storage layer configuration required to enable the mirror or replica LUN in the DR site are performed.
An SR is created for each LUN in the DR site.
VMs are restored from metadata on one or more SRs.
Any adjustments to VM configuration required by differences in the DR site, such as IP addressing, are performed.
VMs are started and verified.
Traffic is routed to the VMs in the DR site.

6.3. VM Snapshots

XenServer provides a convenient snapshotting mechanism that can take a snapshot of a VM storage and metadata at a given time. Where necessary IO is temporarily halted while the snapshot is being taken to ensure that a self-consistent disk image can be captured.

Snapshot operations result in a snapshot VM that is similar to a template. The VM snapshot contains all the storage information and VM configuration, including attached VIFs, allowing them to be exported and restored for backup purposes.

The snapshotting operation is a 2 step process:

Capturing metadata as a template.
Creating a VDI snapshot of the disk(s).

Two types of VM snapshots are supported: regular and quiesced:

6.3.1. Regular Snapshots

Regular snapshots are crash consistent and can be performed on all VM types, including Linux VMs.

6.3.2. Quiesced Snapshots

Quiesced snapshots take advantage of the Windows Volume Shadow Copy Service (VSS) to generate application consistent point-in-time snapshots. The VSS framework helps VSS-aware applications (for example Microsoft Exchange or Microsoft SQL Server) flush data to disk and prepare for the snapshot before it is taken.

Quiesced snapshots are therefore safer to restore, but can have a greater performance impact on a system while they are being taken. They may also fail under load so more than one attempt to take the snapshot may be required.

XenServer supports quiesced snapshots on Windows Server 2003 and Windows Server 2008 for both 32-bit and 64-bit variants. Windows 2000, Windows XP and Windows Vista are not supported. Snapshot is supported on all storage types, though for the LVM-based storage types the storage repository must have been upgraded if it was created on a previous version of XenServer and the volume must be in the default format (type=raw volumes cannot be snapshotted).

Note

Using EqualLogic or NetApp storage requires a Citrix Essentials for XenServer license. To learn more about Citrix Essentials for XenServer and to find out how to upgrade, visit the Citrix website here.

Note

Do not forget to install the Xen VSS provider in the Windows guest in order to support VSS. This is done using the install-XenProvider.cmd script provided with the Windows PV drivers. More details can be found in the Virtual Machine Installation Guide in the Windows section.

In general, a VM can only access VDI snapshots (not VDI clones) of itself using the VSS interface. There is a flag that can be set by the XenServer administrator whereby adding an attribute of snapmanager=true to the VM's other-config allows that VM to import snapshots of VDIs from other VMs.

Warning

This opens a security vulnerability and should be used with care. This feature allows an administrator to attach VSS snapshots using an in-guest transportable snapshot ID as generated by the VSS layer to another VM for the purposes of backup.

VSS quiesce timeout: the Microsoft VSS quiesce period is set to a non-configurable value of 10 seconds, and it is quite probable that a snapshot may not be able to complete in time. If, for example the XAPI daemon has queued additional blocking tasks such as an SR scan, the VSS snapshot may timeout and fail. The operation should be retried if this happens.

Note

The more VBDs attached to a VM, the more likely it is that this timeout may be reached. Citrix recommends attaching no more that 2 VBDs to a VM to avoid reaching the timeout. However, there is a workaround to this problem. The probability of taking a successful VSS based snapshot of a VM with more than 2 VBDs can be increased manifold, if all the VDIs for the VM are hosted on different SRs.

VSS snapshot all the disks attached to a VM: in order to store all data available at the time of a VSS snapshot, the XAPI manager will snapshot all disks and the VM metadata associated with a VM that can be snapshotted using the XenServer storage manager API. If the VSS layer requests a snapshot of only a subset of the disks, a full VM snapshot will not be taken.

Vm-snapshot-with-quiesce produces bootable snapshot VM images: To achieve this end, the XenServer VSS hardware provider makes snapshot volumes writable, including the snapshot of the boot volume.

VSS snap of volumes hosted on dynamic disks in the Windows Guest: The vm-snapshot-with-quiesce CLI and the XenServer VSS hardware provider do not support snapshots of volumes hosted on dynamic disks on the Windows VM.

6.3.3. Taking a VM snapshot

Before taking a snapshot, see the section called “Preparing to clone a Windows VM” in XenServer Virtual Machine Installation Guide and the section called “Preparing to clone a Linux VM” in XenServer Virtual Machine Installation Guide for information about any special operating system-specific configuration and considerations to take into account.

Use the vm-snapshot and vm-snapshot-with-quiesce commands to take a snapshot of a VM:

xe vm-snapshot vm=<vm_name> new-name-label=<vm_snapshot_name>	
xe vm-snapshot-with-quiesce vm=<vm_name> new-name-label=<vm_snapshot_name>

6.3.4. VM Rollback

Restoring a VM to snapshot state

Note

Restoring a VM will not preserve the original VM UUID or MAC address.

Note the name of the snapshot
Note the MAC address of the VM
Destroy the VM:
1. Run the vm-list command to find the UUID of the VM to be destroyed:
```
xe vm-list
```
2. Shutdown the VM:
```
xe vm-shutdown uuid=<vm_uuid>
```
3. Destroy the VM:
```
xe vm-destroy uuid=<vm_uuid>
```

Create a new VM from the snapshot:

xe vm-install new-name-label=<vm_name_label> template=<template_name>

Start the VM:
```
xe vm-start name-label=<vm_name>
```

6.4. Coping with machine failures

This section provides details of how to recover from various failure scenarios. All failure recovery scenarios require the use of one or more of the backup types listed in Section 6.1, “Backups”.

6.4.1. Member failures

In the absence of HA, master nodes detect the failures of members by receiving regular heartbeat messages. If no heartbeat has been received for 200 seconds, the master assumes the member is dead. There are two ways to recover from this problem:

Repair the dead host (e.g. by physically rebooting it). When the connection to the member is restored, the master will mark the member as alive again.
Shutdown the host and instruct the master to forget about the member node using the xe host-forget CLI command. Once the member has been forgotten, all the VMs which were running there will be marked as offline and can be restarted on other XenServer hosts. Note it is very important to ensure that the XenServer host is actually offline, otherwise VM data corruption might occur. Be careful not to split your pool into multiple pools of a single host by using xe host-forget, since this could result in them all mapping the same shared storage and corrupting VM data.
Warning
- If you are going to use the forgotten host as a XenServer host again, perform a fresh installation of the XenServer software.
- Do not use xe host-forget command if HA is enabled on the pool. Disable HA first, then forget the host, and then reenable HA.

When a member XenServer host fails, there may be VMs still registered in the running state. If you are sure that the member XenServer host is definitely down, and that the VMs have not been brought up on another XenServer host in the pool, use the xe vm-reset-powerstate CLI command to set the power state of the VMs to halted. See Section 8.4.23.24, “vm-reset-powerstate” for more details.

Warning

Incorrect use of this command can lead to data corruption. Only use this command if absolutely necessary.

6.4.2. Master failures

Every member of a resource pool contains all the information necessary to take over the role of master if required. When a master node fails, the following sequence of events occurs:

The members realize that communication has been lost and each tries to reconnect for sixty seconds.
Each member then puts itself into emergency mode, whereby the member XenServer hosts will now accept only the pool-emergency commands (xe pool-emergency-reset-master and xe pool-emergency-transition-to-master).

If the master comes back up at this point, it re-establishes communication with its members, the members leave emergency mode, and operation returns to normal.

If the master is really dead, choose one of the members and run the command xe pool-emergency-transition-to-master on it. Once it has become the master, run the command xe pool-recover-slaves and the members will now point to the new master.

If you repair or replace the server that was the original master, you can simply bring it up, install the XenServer host software, and add it to the pool. Since the XenServer hosts in the pool are enforced to be homogeneous, there is no real need to make the replaced server the master.

When a member XenServer host is transitioned to being a master, you should also check that the default pool storage repository is set to an appropriate value. This can be done using the xe pool-param-list command and verifying that the default-SR parameter is pointing to a valid storage repository.

6.4.3. Pool failures

In the unfortunate event that your entire resource pool fails, you will need to recreate the pool database from scratch. Be sure to regularly back up your pool-metadata using the xe pool-dump-database CLI command (see Section 8.4.12.2, “pool-dump-database”).

To restore a completely failed pool

Install a fresh set of hosts. Do not pool them up at this stage.

For the host nominated as the master, restore the pool database from your backup using the xe pool-restore-database (see Section 8.4.12.10, “pool-restore-database”) command.
Connect to the master host using XenCenter and ensure that all your shared storage and VMs are available again.
Perform a pool join operation on the remaining freshly installed member hosts, and start up your VMs on the appropriate hosts.

6.4.4. Coping with Failure due to Configuration Errors

If the physical host machine is operational but the software or host configuration is corrupted:

To restore host software and configuration

If the physical host machine has failed, use the appropriate procedure listed below to recover.

xe host-restore host=<host> file-name=<hostbackup>

Reboot to the host installation CD and select Restore from backup.

6.4.5. Physical Machine failure

Warning

Any VMs which were running on a previous member (or the previous host) which has failed will still be marked as Running in the database. This is for safety -- simultaneously starting a VM on two different hosts would lead to severe disk corruption. If you are sure that the machines (and VMs) are offline you can reset the VM power state to Halted:

xe vm-reset-powerstate vm=<vm_uuid> --force

VMs can then be restarted using XenCenter or the CLI.

Replacing a failed master with a still running member

Run the commands:

xe pool-emergency-transition-to-master
xe pool-recover-slaves

If the commands succeed, restart the VMs.

To restore a pool with all hosts failed

xe pool-restore-database file-name=<backup>

Warning

This command will only succeed if the target machine has an appropriate number of appropriately named NICs.

If the target machine has a different view of the storage (for example, a block-mirror with a different IP address) than the original machine, modify the storage configuration using the pbd-destroy command and then the pbd-create command to recreate storage configurations. See Section 8.4.10, “PBD commands” for documentation of these commands.
If you have created a new storage configuration, use pbd-plug or Storage > Repair Storage Repository menu item in XenCenter to use the new configuration.
Restart all VMs.

To restore a VM when VM storage is not available

xe vm-import filename=<backup> --metadata

If the metadata import fails, run the command:
```
xe vm-import filename=<backup> --metadata --force
```
This command will attempt to restore the VM metadata on a 'best effort' basis.
Restart all VMs.

Chapter 7. Monitoring and managing XenServer

7.2. Custom Fields and Tags

7.1. Alerts

7.1.1. Customizing Alerts
7.1.2. Configuring Email Alerts

7.3. Custom Searches

7.4. Determining throughput of physical bus adapters

XenServer and XenCenter provide access to alerts that are generated when noteworthy things happen. XenCenter provides various mechanisms of grouping and maintaining metadata about managed VMs, hosts, storage repositories, and so on.

Note

Full monitoring and alerting functionality is only available with a Citrix Essentials for XenServer license. To learn more about Citrix Essentials for XenServer and to find out how to upgrade, visit the Citrix website here.

7.1. Alerts

XenServer generates alerts for the following events.

Configurable Alerts:

New XenServer patches available
New XenServer version available
New XenCenter version available

Alerts generated by XenCenter:

Alert	Description
XenCenter old	the XenServer expects a newer version but can still connect to the current version
XenCenter out of date	XenCenter is too old to connect to XenServer
XenServer out of date	XenServer is an old version that the current XenCenter cannot connect to
License expired alert	your XenServer license has expired
Missing IQN alert	XenServer uses iSCSI storage but the host IQN is blank
Duplicate IQN alert	XenServer uses iSCSI storage, and there are duplicate host IQNs

Alerts generated by XenServer:

ha_host_failed
ha_host_was_fenced
ha_network_bonding_error
ha_pool_drop_in_plan_exists_for
ha_pool_overcommitted
ha_protected_vm_restart_failed
ha_statefile_lost
host_clock_skew_detected
host_sync_data_failed
license_does_not_support_pooling
pbd_plug_failed_on_server_start
pool_master_transition

The following alerts appear on the performance graphs in XenCenter. See the XenCenter online help for more information:

vm_cloned
vm_crashed
vm_rebooted
vm_resumed
vm_shutdown
vm_started
vm_suspended

7.1.1. Customizing Alerts

Note

Most alerts are only available in a pool with a Citrix Essentials for XenServer license. To learn more about Citrix Essentials for XenServer and to find out how to upgrade, visit the Citrix website here.

The performance monitoring perfmon runs once every 5 minutes and requests updates from XenServer which are averages over 1 minute, but these defaults can be changed in /etc/sysconfig/perfmon.

Every 5 minutes perfmon reads updates of performance variables exported by the XAPI instance running on the same host. These variables are separated into one group relating to the host itself, and a group for each VM running on that host. For each VM and also for the host, perfmon reads in the other-config:perfmon parameter and uses this string to determine which variables it should monitor, and under which circumstances to generate a message.

vm:other-config:perfmon and host:other-config:perfmon values consist of an XML string like the one below:

<config>
	<variable>
		<name value="cpu_usage"/>
		<alarm_trigger_level value="LEVEL"/>
	</variable>
	<variable>
		<name value="network_usage"/>
		<alarm_trigger_level value="LEVEL"/>
	</variable>
</config>

Valid VM Elements

name: what to call the variable (no default). If the name value is one of cpu_usage, network_usage, or disk_usage the rrd_regex and alarm_trigger_sense parameters are not required as defaults for these values will be used.
alarm_priority: the priority of the messages generated (default 5)
alarm_trigger_level: level of value that triggers an alarm (no default)
alarm_trigger_sense: high if alarm_trigger_level is a maximum value otherwise low if the alarm_trigger_level is a minimum value. (default high)
alarm_trigger_period: number of seconds that values above or below the alarm threshold can be received before an alarm is sent (default 60)
alarm_auto_inhibit_period: number of seconds this alarm disabled after an alarm is sent (default 3600)
consolidation_fn: how to combine variables from rrd_updates into one value (default is sum - other choice is average)
rrd_regex: regular expression to match the names of variables returned by the xe vm-data-source-list uuid=<vmuuid> command that should be used to compute the statistical value. This parameter has defaults for the named variables cpu_usage, network_usage, and disk_usage. If specified, the values of all items returned by xe vm-data-source-list whose names match the specified regular expression will be consolidated using the method specified as the consolidation_fn.

Valid Host Elements

name: what to call the variable (no default)
alarm_priority: the priority of the messages generated (default 5)
alarm_trigger_level: level of value that triggers an alarm (no default)
alarm_trigger_sense: high if alarm_trigger_level is a maximum value otherwise low if the alarm_trigger_level is a minimum value. (default high)
alarm_trigger_period: number of seconds that values above or below the alarm threshold can be received before an alarm is sent (default 60)
alarm_auto_inhibit_period: number of seconds this alarm disabled after an alarm is sent (default 3600)
consolidation_fn: how to combine variables from rrd_updates into one value (default sum - other choice is average)
rrd_regex: regular expression to match the names of variables returned by the xe vm-data-source-list uuid=<vmuuid> command that should be used to compute the statistical value. This parameter has defaults for the named variables cpu_usage and network_usage. If specified, the values of all items returned by xe vm-data-source-list whose names match the specified regular expression will be consolidated using the method specified as the consolidation_fn.

7.1.2. Configuring Email Alerts

Note

Email alerts are only available in a pool with a Citrix Essentials for XenServer license. To learn more about Citrix Essentials for XenServer and to find out how to upgrade, visit the Citrix website here.

Alerts generated from XenServer can also be automatically e-mailed to the resource pool administrator, in addition to being visible from the XenCenter GUI. To configure this, specify the email address and SMTP server:

pool:other-config:mail-destination=<joe.bloggs@domain.tld>
pool:other-config:ssmtp-mailhub=<smtp.domain.tld[:port]>

You can also specify the minimum value of the priority field in the message before the email will be sent:

pool:other-config:mail-min-priority=<level>

The default priority level is 5.

Note

Some SMTP servers only forward mails with addresses that use FQDNs. If you find that emails are not being forwarded it may be for this reason, in which case you can set the server hostname to the FQDN so this is used when connecting to your mail server.

7.2. Custom Fields and Tags

XenCenter supports the creation of tags and custom fields, which allows for organization and quick searching of VMs, storage and so on. See the XenCenter online help for more information.

7.3. Custom Searches

XenCenter supports the creation of customized searches. Searches can be exported and imported, and the results of a search can be displayed in the navigation pane. See the XenCenter online help for more information.

7.4. Determining throughput of physical bus adapters

For FC, SAS and iSCSI HBAs you can determine the network throughput of your PBDs using the following procedure.

To determine PBD throughput

List the PBDs on a host.
Determine which LUNs are routed over which PBDs.
For each PBD and SR, list the VBDs that reference VDIs on the SR.
For all active VBDs that are attached to VMs on the host, calculate the combined throughput.

For iSCSI and NFS storage, check your network statistics to determine if there is a throughput bottleneck at the array, or whether the PBD is saturated.

Chapter 8. Command line interface

This chapter describes the XenServer command line interface (CLI). The xe CLI enables the writing of scripts for automating system administration tasks and allows integration of XenServer into an existing IT infrastructure.

The xe command line interface is installed by default on XenServer hosts and is included with XenCenter. A stand-alone remote CLI is also available for Linux.

On Windows, the xe.exe CLI executable is installed along with XenCenter.

To use it, open a Windows Command Prompt and change directories to the directory where the file resides (typically C:\Program Files\XenSource\XenCenter), or add its installation location to your system path.

On Linux, you can install the stand-alone xe CLI executable from the RPM named xe-cli-5.5.0-24648c.i386.rpm on the Linux Pack CD, as follows:

rpm -ivh xe-cli-5.5.0-24648c.i386.rpm

Basic help is available for CLI commands on-host by typing:

xe help command

A list of the most commonly-used xe commands is displayed if you type:

xe help

or a list of all xe commands is displayed if you type:

xe help --all

8.1. Basic xe syntax

The basic syntax of all XenServer xe CLI commands is:

xe <command-name> <argument=value> <argument=value> ...

Each specific command contains its own set of arguments that are of the form argument=value. Some commands have required arguments, and most have some set of optional arguments. Typically a command will assume default values for some of the optional arguments when invoked without them.

If the xe command is executed remotely, additional connection and authentication arguments are used. These arguments also take the form argument=argument_value.

The server argument is used to specify the hostname or IP address. The username and password arguments are used to specify credentials. A password-file argument can be specified instead of the password directly. In this case an attempt is made to read the password from the specified file (stripping CRs and LFs off the end of the file if necessary), and use that to connect. This is more secure than specifying the password directly at the command line.

The optional port argument can be used to specify the agent port on the remote XenServer host (defaults to 443).

Example: On the local XenServer host:

xe vm-list

Example: On the remote XenServer host:

xe vm-list -user <username> -password <password> -server <hostname>

Shorthand syntax is also available for remote connection arguments:

-u	username
-pw	password
-pwf	password file
-p	port
-s	server

Example: On a remote XenServer host:

xe vm-list -u <myuser> -pw <mypassword> -s <hostname>

Arguments are also taken from the environment variable XE_EXTRA_ARGS, in the form of comma-separated key/value pairs. For example, in order to enter commands on one XenServer host that are run on a remote XenServer host, you could do the following:

export XE_EXTRA_ARGS="server=jeffbeck,port=443,username=root,password=pass"

and thereafter you would not need to specify the remote XenServer host parameters in each xe command you execute.

Using the XE_EXTRA_ARGS environment variable also enables tab completion of xe commands when issued against a remote XenServer host, which is disabled by default.

8.2. Special characters and syntax

To specify argument/value pairs on the xe command line, write

argument=value

without quotes, as long as value doesn't have any spaces in it. There should be no whitespace in between the argument name, the equals sign (=), and the value. Any argument not conforming to this format will be ignored.

For values containing spaces, write:

argument="value with spaces"

If you use the CLI while logged into a XenServer host, commands have a tab completion feature similar to that in the standard Linux bash shell. If you type, for example

xe vm-l

and then press the TAB key, the rest of the command will be displayed when it is unambiguous. If more than one command begins with vm-l, hitting TAB a second time will list the possibilities. This is particularly useful when specifying object UUIDs in commands.

Note

When executing commands on a remote XenServer host, tab completion does not normally work. However if you put the server, username, and password in an environment variable called XE_EXTRA_ARGS on the machine from which you are entering the commands, tab completion is enabled. See Section 8.1, “Basic xe syntax” for details.

8.3. Command types

Broadly speaking, the CLI commands can be split in two halves: Low-level commands concerned with listing and parameter manipulation of API objects, and higher level commands for interacting with VMs or hosts in a more abstract level. The low-level commands are:

<class>-list
<class>-param-get
<class>-param-set
<class>-param-list
<class>-param-add
<class>-param-remove
<class>-param-clear

where <class> is one of:

bond
console
host
host-crashdump
host-cpu
network
patch
pbd
pif
pool
sm
sr
task
template
vbd
vdi
vif
vlan
vm

Note that not every value of <class> has the full set of <class>-param- commands; some have just a subset.

8.3.1. Parameter types

The objects that are addressed with the xe commands have sets of parameters that identify them and define their states.

Most parameters take a single value. For example, the name-label parameter of a VM contains a single string value. In the output from parameter list commands such as xe vm-param-list, such parameters have an indication in parentheses that defines whether they can be read and written to, or are read-only. For example, the output of xe vm-param-list on a specified VM might have the lines

user-version ( RW): 1
 is-control-domain ( RO): false

The first parameter, user-version, is writeable and has the value 1. The second, is-control-domain, is read-only and has a value of false.

The two other types of parameters are multi-valued. A set parameter contains a list of values. A map parameter is a set of key/value pairs. As an example, look at the following excerpt of some sample output of the xe vm-param-list on a specified VM:

platform (MRW): acpi: true; apic: true; pae: true; nx: false
allowed-operations (SRO): pause; clean_shutdown; clean_reboot; \
hard_shutdown; hard_reboot; suspend

The platform parameter has a list of items that represent key/value pairs. The key names are followed by a colon character (:). Each key/value pair is separated from the next by a semicolon character (;). The M preceding the RW indicates that this is a map parameter and is readable and writeable. The allowed-operations parameter has a list that makes up a set of items. The S preceding the RO indicates that this is a set parameter and is readable but not writeable.

In xe commands where you want to filter on a map parameter, or set a map parameter, use the separator : (colon) between the map parameter name and the key/value pair. For example, to set the value of the foo key of the other-config parameter of a VM to baa, the command would be

xe vm-param-set uuid=<VM uuid> other-config:foo=baa

Note

In previous releases the separator - (dash) was used in specifying map parameters. This syntax still works but is deprecated.

8.3.2. Low-level param commands

There are several commands for operating on parameters of objects: <class>-param-get, <class>-param-set, <class>-param-add, <class>-param-remove, <class>-param-clear, and <class>-param-list. Each of these takes a uuid parameter to specify the particular object. Since these are considered low-level commands, they must be addressed by UUID and not by the VM name label.

<class>-param-list uuid=<uuid>: Lists all of the parameters and their associated values. Unlike the class-list command, this will list the values of "expensive" fields.
<class>-param-get uuid=<uuid> param-name=<parameter> [param-key=<key>]: Returns the value of a particular parameter. If the parameter is a map, specifying the param-key will get the value associated with that key in the map. If param-key is not specified, or if the parameter is a set, it will return a string representation of the set or map.
<class>-param-set uuid=<uuid> param=<value>...: Sets the value of one or more parameters.
<class>-param-add uuid=<uuid> param-name=<parameter> [<key>=<value>...] [param-key=<key>]: Adds to either a map or a set parameter. If the parameter is a map, add key/value pairs using the <key>=<value> syntax. If the parameter is a set, add keys with the <param-key>=<key> syntax.
<class>-param-remove uuid=<uuid> param-name=<parameter> param-key=<key>: Removes either a key/value pair from a map, or a key from a set.
<class>-param-clear uuid=<uuid> param-name=<parameter>: Completely clears a set or a map.

8.3.3. Low-level list commands

The <class>-list command lists the objects of type <class>. By default it will list all objects, printing a subset of the parameters. This behavior can be modified in two ways: it can filter the objects so that it only outputs a subset, and the parameters that are printed can be modified.

To change the parameters that are printed, the argument params should be specified as a comma-separated list of the required parameters, e.g.:

xe vm-list params=name-label,other-config

Alternatively, to list all of the parameters, use the syntax:

xe vm-list params=all

Note that some parameters that are expensive to calculate will not be shown by the list command. These parameters will be shown as, for example:

allowed-VBD-devices (SRO): <expensive field>

To obtain these fields, use either the command <class>-param-list or <class>-param-get

To filter the list, the CLI will match parameter values with those specified on the command-line, only printing object that match all of the specified constraints. For example:

xe vm-list HVM-boot-policy="BIOS order" power-state=halted

will only list those VMs for which both the field power-state has the value halted, and for which the field HVM-boot-policy has the value BIOS order.

It is also possible to filter the list based on the value of keys in maps, or on the existence of values in a set. The syntax for the first of these is map-name:key=value, and the second is set-name:contains=value

For scripting, a useful technique is passing --minimal on the command line, causing xe to print only the first field in a comma-separated list. For example, the command xe vm-list --minimal on a XenServer host with three VMs installed gives the three UUIDs of the VMs, for example:

a85d6717-7264-d00e-069b-3b1d19d56ad9,aaa3eec5-9499-bcf3-4c03-af10baea96b7, \
42c044de-df69-4b30-89d9-2c199564581d

8.4. xe command reference

This section provides a reference to the xe commands. They are grouped by objects that the commands address, and listed alphabetically.

8.4.1. Bonding commands

Commands for working with network bonds, for resilience with physical interface failover. See Section 4.2.4, “Creating NIC bonds on a standalone host” for details.

The bond object is a reference object which glues together master and member PIFs. The master PIF is the bonding interface which must be used as the overall PIF to refer to the bond. The member PIFs are a set of 2 or more physical interfaces which have been combined into the high-level bonded interface.

Bond parameters

Bonds have the following parameters:

Parameter Name	Description	Type
uuid	unique identifier/object reference for the bond	read only
master	UUID for the master bond PIF	read only
members	set of UUIDs for the underlying bonded PIFs	read only set parameter

8.4.1.1. bond-create

bond-create network-uuid=<network_uuid> pif-uuids=<pif_uuid_1,pif_uuid_2,...>

Create a bonded network interface on the network specified from a list of existing PIF objects. The command will fail if PIFs are in another bond already, if any member has a VLAN tag set, if the referenced PIFs are not on the same XenServer host, or if fewer than 2 PIFs are supplied.

8.4.1.2. bond-destroy

host-bond-destroy uuid=<bond_uuid>

Delete a bonded interface specified by its UUID from the XenServer host.

8.4.2. CD commands

Commands for working with physical CD/DVD drives on XenServer hosts.

CD parameters

CDs have the following parameters:

Parameter Name	Description	Type
uuid	unique identifier/object reference for the CD	read only
name-label	Name for the CD	read/write
name-description	Description text for the CD	read/write
allowed-operations	A list of the operations that can be performed on this CD	read only set parameter
current-operations	A list of the operations that are currently in progress on this CD	read only set parameter
sr-uuid	The unique identifier/object reference for the SR this CD is part of	read only
sr-name-label	The name for the SR this CD is part of	read only
vbd-uuids	A list of the unique identifiers for the VBDs on VMs that connect to this CD	read only set parameter
crashdump-uuids	Not used on CDs since crashdumps cannot be written to them	read only set parameter
virtual-size	Size of the CD as it appears to VMs (in bytes)	read only
physical-utilisation	amount of physical space that the CD image is currently taking up on the SR (in bytes)	read only
type	Set to `User` for CDs	read only
sharable	Whether or not the CD drive is sharable. Default is false.	read only
read-only	Whether the CD is read-only, if false, the device is writeable. Always true for CDs.	read only
storage-lock	true if this disk is locked at the storage level	read only
parent	Reference to the parent disk, if this CD is part of a chain	read only
missing	true if SR scan operation reported this CD as not present on disk	read only
other-config	A list of key/value pairs that specify additional configuration parameters for the CD	read/write map parameter
location	The path on which the device is mounted	read only
managed	true if the device is managed	read only
xenstore-data	Data to be inserted into the xenstore tree	read only map parameter
sm-config	names and descriptions of storage manager device config keys	read only map parameter
is-a-snapshot	True if this template is a CD snapshot	read only
snapshot_of	The UUID of the CD that this template is a snapshot of	read only
snapshots	The UUID(s) of any snapshots that have been taken of this CD	read only
snapshot_time	The timestamp of the snapshot operation	read only

8.4.2.1. cd-list

cd-list [params=<param1,param2,...>] [parameter=<parameter_value>...]

List the CDs and ISOs (CD image files) on the XenServer host or pool, filtering on the optional argument params.

If the optional argument params is used, the value of params is a string containing a list of parameters of this object that you want to display. Alternatively, you can use the keyword all to show all parameters. If params is not used, the returned list shows a default subset of all available parameters.

Optional arguments can be any number of the CD parameters listed at the beginning of this section.

8.4.3. Console commands

Commands for working with consoles.

The console objects can be listed with the standard object listing command (xe console-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

Console parameters

Consoles have the following parameters:

Parameter Name	Description	Type
uuid	The unique identifier/object reference for the console	read only
vm-uuid	The unique identifier/object reference of the VM this console is open on	read only
vm-name-label	The name of the VM this console is open on	read only
protocol	Protocol this console uses. Possible values are `vt100`: VT100 terminal, `rfb`: Remote FrameBuffer protocol (as used in VNC), or `rdp`: Remote Desktop Protocol	read only
location	URI for the console service	read only
other-config	A list of key/value pairs that specify additional configuration parameters for the console.	read/write map parameter

8.4.4. Event commands

Commands for working with events.

Event classes

Event classes are listed in the following table:

Class name	Description
pool	A pool of physical hosts
vm	A Virtual Machine
host	A physical host
network	A virtual network
vif	A virtual network interface
pif	A physical network interface (separate VLANs are represented as several PIFs)
sr	A storage repository
vdi	A virtual disk image
vbd	A virtual block device
pbd	The physical block devices through which hosts access SRs

8.4.4.1. event-wait

event-wait class=<class_name> [<param-name>=<param_value>] [<param-name>=/=<param_value>]

Block other commands from executing until an object exists that satisfies the conditions given on the command line. x=y means "wait for field x to take value y", and x=/=y means "wait for field x to take any value other than y".

Example: wait for a specific VM to be running

xe event-wait class=vm name-label=myvm power-state=running

blocks until a VM called myvm is in the power-state "running."

Example: wait for a specific VM to reboot:

xe event-wait class=vm uuid=$VM start-time=/=$(xe vm-list uuid=$VM params=start-time --minimal)

blocks until a VM with UUID $VM reboots (i.e. has a different start-time value).

The class name can be any of the Event classes listed at the beginning of this section, and the parameters can be any of those listed in the CLI command class-param-list.

8.4.5. Host (XenServer host) commands

Commands for interacting with XenServer host.

XenServer hosts are the physical servers running XenServer software. They have VMs running on them under the control of a special privileged Virtual Machine, known as the control domain or domain 0.

The XenServer host objects can be listed with the standard object listing command (xe host-list, xe host-cpu-list, and xe host-crashdump-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

Host selectors

Several of the commands listed here have a common mechanism for selecting one or more XenServer hosts on which to perform the operation. The simplest is by supplying the argument host=<uuid_or_name_label>. XenServer hosts can also be specified by filtering the full list of hosts on the values of fields. For example, specifying enabled=true will select all XenServer hosts whose enabled field is equal to true. Where multiple XenServer hosts are matching, and the operation can be performed on multiple XenServer hosts, the option --multiple must be specified to perform the operation. The full list of parameters that can be matched is described at the beginning of this section, and can be obtained by running the command xe host-list params=all. If no parameters to select XenServer hosts are given, the operation will be performed on all XenServer hosts.

Host parameters

XenServer hosts have the following parameters:

Parameter Name	Description	Type
uuid	The unique identifier/object reference for the XenServer host	read only
name-label	The name of the XenServer host	read/write
name-description	The description string of the XenServer host	read only
enabled	false if disabled which prevents any new VMs from starting on them, which prepares the XenServer hosts to be shut down or rebooted; true if the host is currently enabled	read only
API-version-major	major version number	read only
API-version-minor	minor version number	read only
API-version-vendor	identification of API vendor	read only
API-version-vendor-implementation	details of vendor implementation	read only map parameter
logging	logging configuration	read/write map parameter
suspend-image-sr-uuid	the unique identifier/object reference for the SR where suspended images are put	read/write
crash-dump-sr-uuid	the unique identifier/object reference for the SR where crash dumps are put	read/write
software-version	list of versioning parameters and their values	read only map parameter
capabilities	list of Xen versions that the XenServer host can run	read only set parameter
other-config	A list of key/value pairs that specify additional configuration parameters for the XenServer host	read/write map parameter
hostname	XenServer host hostname	read only
address	XenServer host IP address	read only
supported-bootloaders	list of bootloaders that the XenServer host supports, for example, pygrub, eliloader	read only set parameter
memory-total	total amount of physical RAM on the XenServer host, in bytes	read only
memory-free	total amount of physical RAM remaining that can be allocated to VMs, in bytes	read only
host-metrics-live	true if the host is operational	read only
logging	The `syslog_destination` key can be set to the hostname of a remote listening syslog service.	read/write map parameter
allowed-operations	lists the operations allowed in this state. This list is advisory only and the server state may have changed by the time this field is read by a client.	read only set parameter
current-operations	lists the operations currently in process. This list is advisory only and the server state may have changed by the time this field is read by a client	read only set parameter
patches	Set of host patches	read only set parameter
blobs	Binary data store	read only
memory-free-computed	A conservative estimate of the maximum amount of memory free on a host	read only
ha-statefiles	The UUID(s) of all HA statefiles	read only
ha-network-peers	The UUIDs of all hosts that could host the VMs on this host in case of failure	read only
external-auth-type	Type of external authentication, for example, Active Directory.	read only
external-auth-service-name	The name of the external authentication service	read only
external-auth-configuration	Configuration information for the external authentication service.	read only map parameter

XenServer hosts contain some other objects that also have parameter lists.

CPUs on XenServer hosts have the following parameters:

Parameter Name	Description	Type
uuid	The unique identifier/object reference for the CPU	read only
number	the number of the physical CPU core within the XenServer host	read only
vendor	the vendor string for the CPU name, for example, "GenuineIntel"	read only
speed	The CPU clock speed, in Hz	read only
modelname	the vendor string for the CPU model, for example, "Intel(R) Xeon(TM) CPU 3.00GHz"	read only
stepping	the CPU revision number	read only
flags	the flags of the physical CPU (a decoded version of the features field)	read only
utilisation	the current CPU utilization	read only
host-uuid	the UUID if the host the CPU is in	read only
model	the model number of the physical CPU	read only
family	the physical CPU family number	read only

Crash dumps on XenServer hosts have the following parameters:

Parameter Name	Description	Type
uuid	The unique identifier/object reference for the crashdump	read only
host	XenServer host the crashdump corresponds to	read only
timestamp	Timestamp of the date and time that the crashdump occurred, in the form yyyymmdd-hhmmss-ABC, where ABC is the timezone indicator, for example, GMT	read only
size	size of the crashdump, in bytes	read only

8.4.5.1. host-backup

host-backup file-name=<backup_filename> host=<host_name>

Download a backup of the control domain of the specified XenServer host to the machine that the command is invoked from, and save it there as a file with the name file-name.

Caution

While the xe host-backup command will work if executed on the local host (that is, without a specific hostname specified), do not use it this way. Doing so would fill up the control domain partition with the backup file. The command should only be used from a remote off-host machine where you have space to hold the backup file.

8.4.5.2. host-bugreport-upload

host-bugreport-upload [<host-selector>=<host_selector_value>...] [url=<destination_url>]
[http-proxy=<http_proxy_name>]

Generate a fresh bug report (using xen-bugtool, with all optional files included) and upload to the Citrix Support ftp site or some other location.

The host(s) on which this operation should be performed are selected using the standard selection mechanism (see host selectors above). Optional arguments can be any number of the host selectors listed at the beginning of this section.

Optional parameters are http-proxy: use specified http proxy, and url: upload to this destination URL. If optional parameters are not used, no proxy server is identified and the destination will be the default Citrix Support ftp site.

8.4.5.3. host-crashdump-destroy

host-crashdump-destroy uuid=<crashdump_uuid>

Delete a host crashdump specified by its UUID from the XenServer host.

8.4.5.4. host-crashdump-upload

host-crashdump-upload uuid=<crashdump_uuid>
[url=<destination_url>]
[http-proxy=<http_proxy_name>]

Upload a crashdump to the Citrix Support ftp site or other location. If optional parameters are not used, no proxy server is identified and the destination will be the default Citrix Support ftp site. Optional parameters are http-proxy: use specified http proxy, and url: upload to this destination URL.

8.4.5.5. host-disable

host-disable [<host-selector>=<host_selector_value>...]

Disables the specified XenServer hosts, which prevents any new VMs from starting on them. This prepares the XenServer hosts to be shut down or rebooted.

8.4.5.6. host-dmesg

host-dmesg [<host-selector>=<host_selector_value>...]

Get a Xen dmesg (the output of the kernel ring buffer) from specified XenServer hosts.

8.4.5.7. host-emergency-management-reconfigure

host-emergency-management-reconfigure interface=<uuid_of_management_interface_pif>

Reconfigure the management interface of this XenServer host. Use this command only if the XenServer host is in emergency mode, meaning that it is a member in a resource pool whose master has disappeared from the network and could not be contacted for some number of retries.

8.4.5.8. host-enable

host-enable [<host-selector>=<host_selector_value>...]

Enables the specified XenServer hosts, which allows new VMs to be started on them.

8.4.5.9. host-evacuate

host-evacuate [<host-selector>=<host_selector_value>...]

Live migrates all running VMs to other suitable hosts on a pool. The host must first be disabled using the host-disable command.

If the evacuated host is the pool master, then another host must be selected to be the pool master. To change the pool master with HA disabled, you need to use the pool-designate-new-master command. See Section 8.4.12.1, “pool-designate-new-master” for details. With HA enabled, your only option is to shut down the server, which will cause HA to elect a new master at random. See Section 8.4.5.22, “host-shutdown”.

8.4.5.10. host-forget

host-forget uuid=<XenServer_host_UUID>

The xapi agent forgets about the specified XenServer host without contacting it explicitly.

Use the --force parameter to avoid being prompted to confirm that you really want to perform this operation.

Warning

Don't use this command if HA is enabled on the pool. Disable HA first, then enable it again after you've forgotten the host.

Tip

This command is useful if the XenServer host to "forget" is dead; however, if the XenServer host is live and part of the pool, you should use xe pool-eject instead.

8.4.5.11. host-get-system-status

host-get-system-status filename=<name_for_status_file>
[entries=<comma_separated_list>] [output=<tar.bz2 | zip>] [<host-selector>=<host_selector_value>...]

Download system status information into the specified file. The optional parameter entries is a comma-separated list of system status entries, taken from the capabilities XML fragment returned by the host-get-system-status-capabilities command. See Section 8.4.5.12, “host-get-system-status-capabilities” for details. If not specified, all system status information is saved in the file. The parameter output may be tar.bz2 (the default) or zip; if this parameter is not specified, the file is saved in tar.bz2 form.

The host(s) on which this operation should be performed are selected using the standard selection mechanism (see host selectors above).

8.4.5.12. host-get-system-status-capabilities

host-get-system-status-capabilities [<host-selector>=<host_selector_value>...]

Get system status capabilities for the specified host(s). The capabilities are returned as an XML fragment that looks something like this:

<?xml version="1.0" ?>	<system-status-capabilities>
 		<capability content-type="text/plain" default-checked="yes" key="xenserver-logs"  \
           max-size="150425200" max-time="-1" min-size="150425200" min-time="-1" \
		   pii="maybe"/>
 		<capability content-type="text/plain" default-checked="yes" \
		   key="xenserver-install" max-size="51200" max-time="-1" min-size="10240" \
		   min-time="-1" pii="maybe"/>
 		...
	</system-status-capabilities>

Each capability entity has a number of attributes.

Attribute	Description
key	A unique identifier for the capability.
content-type	Can be either text/plain or application/data. Indicates whether a UI can render the entries for human consumption.
default-checked	Can be either yes or no. Indicates whether a UI should select this entry by default.
min-size, max-size	Indicates an approximate range for the size, in bytes, of this entry. -1 indicates that the size is unimportant.
min-time, max-time	Indicate an approximate range for the time, in seconds, taken to collect this entry. `-1` indicates the time is unimportant.
pii	Personally identifiable information. Indicates whether the entry would have information that would identify the system owner, or details of their network topology. This is one of: no: no PII will be in these entries yes: PII will likely or certainly be in these entries maybe: you might wish to audit these entries for PII if_customized if the files are unmodified, then they will contain no PII, but since we encourage editing of these files, PII may have been introduced by such customization. This is used in particular for the networking scripts in the control domain. Passwords are never to be included in any bug report, regardless of any PII declaration.

The host(s) on which this operation should be performed are selected using the standard selection mechanism (see host selectors above).

8.4.5.13. host-is-in-emergency-mode

host-is-in-emergency-mode

Returns true if the host the CLI is talking to is currently in emergency mode, false otherwise. This CLI command works directly on slave hosts even with no master host present.

8.4.5.14. host-license-add

host-license-add license-file=<path/license_filename> [host-uuid=<XenServer_host_UUID>]

Parses a local license file and adds it to the specified XenServer host.

For details on licensing a host, see Chapter 5, XenServer Licensing in XenServer Installation Guide.

8.4.5.15. host-license-view

host-license-view [host-uuid=<XenServer_host_UUID>]

Displays the contents of the XenServer host license.

8.4.5.16. host-logs-download

host-logs-download [file-name=<logfile_name>] [<host-selector>=<host_selector_value>...]

Download a copy of the logs of the specified XenServer hosts. The copy is saved by default in a timestamped file named hostname-yyyy-mm-dd T hh:mm:ssZ.tar.gz. You can specify a different filename using the optional parameter file-name.

Caution

While the xe host-logs-download command will work if executed on the local host (that is, without a specific hostname specified), do not use it this way. Doing so will clutter the control domain partition with the copy of the logs. The command should only be used from a remote off-host machine where you have space to hold the copy of the logs.

8.4.5.17. host-management-disable

host-management-disable

Disables the host agent listening on an external management network interface and disconnects all connected API clients (such as the XenCenter). Operates directly on the XenServer host the CLI is connected to, and is not forwarded to the pool master if applied to a member XenServer host.

Warning

Be extremely careful when using this CLI command off-host, since once it is run it will not be possible to connect to the control domain remotely over the network to re-enable it.

8.4.5.18. host-management-reconfigure

host-management-reconfigure [interface=<device> ] | [pif-uuid=<uuid> ]

Reconfigures the XenServer host to use the specified network interface as its management interface, which is the interface that is used to connect to the XenCenter. The command rewrites the MANAGEMENT_INTERFACE key in /etc/xensource-inventory.

If the device name of an interface (which must have an IP address) is specified, the XenServer host will immediately rebind. This works both in normal and emergency mode.

If the UUID of a PIF object is specified, the XenServer host determines which IP address to rebind to itself. It must not be in emergency mode when this command is executed.

Warning

Be careful when using this CLI command off-host and ensure you have network connectivity on the new interface (by using xe pif-reconfigure to set one up first). Otherwise, subsequent CLI commands will not be able to reach the XenServer host.

8.4.5.19. host-reboot

host-reboot [<host-selector>=<host_selector_value>...]

Reboot the specified XenServer hosts. The specified XenServer hosts must be disabled first using the xe host-disable command, otherwise a HOST_IN_USE error message is displayed.

8.4.5.20. host-restore

host-restore [file-name=<backup_filename>] [<host-selector>=<host_selector_value>...]

Restore a backup named file-name of the XenServer host control software. Note that the use of the word "restore" here does not mean a full restore in the usual sense, it merely means that the compressed backup file has been uncompressed and unpacked onto the secondary partition. After you've done a xe host-restore, you have to boot the Install CD and use its Restore from Backup option.

8.4.5.21. host-set-hostname-live

host-set-hostname host-uuid=<uuid_of_host> hostname=<new_hostname>

Change the hostname of the XenServer host specified by host-uuid. This command persistently sets both the hostname in the control domain database and the actual Linux hostname of the XenServer host. Note that hostname is not the same as the value of the name_label field.

8.4.5.22. host-shutdown

host-shutdown [<host-selector>=<host_selector_value>...]

Shut down the specified XenServer hosts. The specified XenServer hosts must be disabled first using the xe host-disable command, otherwise a HOST_IN_USE error message is displayed.

If the specified XenServer hosts are members of a pool, the loss of connectivity on shutdown will be handled and the pool will recover when the XenServer hosts returns. If you shut down a pool member, other members and the master will continue to function. If you shut down the master, the pool will be out of action until the master is rebooted and back on line, at which point the members will reconnect and synchronize with the master, or until one of the members is made into the master. If HA is enabled for the pool, one of the members will be made into a master automatically. If HA is disabled, you must manually designate the desired server as master with the pool-designate-new-master command. See Section 8.4.12.1, “pool-designate-new-master”.

8.4.5.23. host-syslog-reconfigure

host-syslog-reconfigure [<host-selector>=<host_selector_value>...]

Reconfigure the syslog daemon on the specified XenServer hosts. This command applies the configuration information defined in the host logging parameter.

8.4.6. Log commands

Commands for working with logs.

8.4.6.1. log-get-keys

log-get-keys

List the keys of all of the logging subsystems.

8.4.6.2. log-reopen

log-reopen

Reopen all loggers. Use this command for rotating log files.

8.4.6.3. log-set-output

Set the output of the specified logger. Log messages are filtered by the subsystem in which they originated and the log level of the message. For example, send debug logging messages from the storage manager to a file by running the following command:

xe log-set-output key=sm level=debug output=<file:/tmp/sm.log>

The optional parameter key specifies the particular logging subsystem. If this parameter is not set, it will default to all logging subsystems.

The optional parameter level specifies the logging level. Valid values are:

debug
info
warning
error

8.4.7. Message commands

Commands for working with messages. Messages are created to notify users of significant events, and are displayed in XenCenter as system alerts.

Message parameters

Parameter Name	Description	Type
uuid	The unique identifier/object reference for the message	read only
name	The unique name of the message	read only
priority	The message priority. Higher numbers indicate greater priority	read only
class	The message class, for example VM.	read only
obj-uuid	The uuid of the affected object.	read only
timestamp	The time that the message was generated.	read only
body	The message content.	read only

8.4.7.1. message-create

message-create name=<message_name> body=<message_text> [[host-uuid=<uuid_of_host>] | [sr-uuid=<uuid_of_sr>] | [vm-uuid=<uuid_of_vm>] | [pool-uuid=<uuid_of_pool>]]

Creates a new message.

8.4.7.2. message-list

message-list

Lists all messages, or messages that match the specified standard selectable parameters.

8.4.8. Network commands

Commands for working with networks.

The network objects can be listed with the standard object listing command (xe network-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

Network parameters

Networks have the following parameters:

Parameter Name	Description	Type
uuid	The unique identifier/object reference for the network	read only
name-label	The name of the network	read write
name-description	The description text of the network	read write
VIF-uuids	A list of unique identifiers of the VIFs (virtual network interfaces) that are attached from VMs to this network	read only set parameter
PIF-uuids	A list of unique identifiers of the PIFs (physical network interfaces) that are attached from XenServer hosts to this network	read only set parameter
bridge	name of the bridge corresponding to this network on the local XenServer host	read only
other-config:static-routes	comma-separated list of <subnet>/<netmask>/<gateway> formatted entries specifying the gateway address via which to route subnets. For example, setting `other-config:static-routes` to `172.16.0.0/15/192.168.0.3,172.18.0.0/16/192.168.0.4` causes traffic on `172.16.0.0/15` to be routed over `192.168.0.3` and traffic on `172.18.0.0/16` to be routed over `192.168.0.4`.	read write
other-config:ethtool-autoneg	set to `no` to disable autonegotiation of the physical interface or bridge. Default is `yes`.	read write
other-config:ethtool-rx	set to `on` to enable receive checksum, `off` to disable	read write
other-config:ethtool-tx	set to `on` to enable transmit checksum, `off` to disable	read write
other-config:ethtool-sg	set to `on` to enable scatter gather, `off` to disable	read write
other-config:ethtool-tso	set to `on` to enable tcp segmentation offload, `off` to disable	read write
other-config:ethtool-ufo	set to `on` to enable UDP fragment offload, `off` to disable	read write
other-config:ethtool-gso	set to `on` to enable generic segmentation offload, `off` to disable	read write
blobs	Binary data store	read only

8.4.8.1. network-create

network-create name-label=<name_for_network> [name-description=<descriptive_text>]

Creates a new network.

8.4.8.2. network-destroy

network-destroy uuid=<network_uuid>

Destroys an existing network.

8.4.9. Patch (update) commands

Commands for working with XenServer host patches (updates). These are for the standard non-OEM editions of XenServer for commands relating to updating the OEM edition of XenServer, see Section 8.4.17, “Update commands” for details.

The patch objects can be listed with the standard object listing command (xe patch-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

Patch parameters

Patches have the following parameters:

Parameter Name	Description	Type
uuid	The unique identifier/object reference for the patch	read only
host-uuid	The unique identifier for the XenServer host to query	read only
name-label	The name of the patch	read only
name-description	The description string of the patch	read only
applied	Whether or not the patch has been applied; true or false	read only
size	Whether or not the patch has been applied; true or false	read only

8.4.9.1. patch-apply

patch-apply uuid=<patch_file_uuid>

Apply the specified patch file.

8.4.9.2. patch-clean

patch-clean uuid=<patch_file_uuid>

Delete the specified patch file from the XenServer host.

8.4.9.3. patch-pool-apply

patch-pool-apply uuid=<patch_uuid>

Apply the specified patch to all XenServer hosts in the pool.

8.4.9.4. patch-precheck

patch-precheck uuid=<patch_uuid> host-uuid=<host_uuid>

Run the prechecks contained within the specified patch on the specified XenServer host.

8.4.9.5. patch-upload

patch-upload file-name=<patch_filename>

Upload a specified patch file to the XenServer host. This prepares a patch to be applied. On success, the UUID of the uploaded patch is printed out. If the patch has previously been uploaded, a PATCH_ALREADY_EXISTS error is returned instead and the patch is not uploaded again.

8.4.10. PBD commands

Commands for working with PBDs (Physical Block Devices). These are the software objects through which the XenServer host accesses storage repositories (SRs).

The PBD objects can be listed with the standard object listing command (xe pbd-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

PBD parameters

PBDs have the following parameters:

Parameter Name	Description	Type
uuid	The unique identifier/object reference for the PBD.	read only
sr-uuid	the storage repository that the PBD points to	read only
device-config	additional configuration information that is provided to the SR-backend-driver of a host	read only map parameter
currently-attached	True if the SR is currently attached on this host, False otherwise	read only
host-uuid	UUID of the physical machine on which the PBD is available	read only
host	The host field is deprecated. Use host_uuid instead.	read only
other-config	Additional configuration information.	read/write map parameter

8.4.10.1. pbd-create

pbd-create host-uuid=<uuid_of_host>
sr-uuid=<uuid_of_sr>
[device-config:key=<corresponding_value>...]

Create a new PBD on a XenServer host. The read-only device-config parameter can only be set on creation.

To add a mapping of 'path' -> '/tmp', the command line should contain the argument device-config:path=/tmp

For a full list of supported device-config key/value pairs on each SR type see Chapter 3, Storage.

8.4.10.2. pbd-destroy

pbd-destroy uuid=<uuid_of_pbd>

Destroy the specified PBD.

8.4.10.3. pbd-plug

pbd-plug uuid=<uuid_of_pbd>

Attempts to plug in the PBD to the XenServer host. If this succeeds, the referenced SR (and the VDIs contained within) should then become visible to the XenServer host.

8.4.10.4. pbd-unplug

pbd-unplug uuid=<uuid_of_pbd>

Attempt to unplug the PBD from the XenServer host.

8.4.11. PIF commands

Commands for working with PIFs (objects representing the physical network interfaces).

The PIF objects can be listed with the standard object listing command (xe pif-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

PIF parameters

PIFs have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the PIF	read only
device	machine-readable name of the interface (for example, eth0)	read only
MAC	the MAC address of the PIF	read only
other-config	Additional PIF configuration name:value pairs.	read/write map parameter
physical	if true, the PIF points to an actual physical network interface	read only
currently-attached	is the PIF currently attached on this host? true or false	read only
MTU	Maximum Transmission Unit of the PIF in bytes.	read only
VLAN	VLAN tag for all traffic passing through this interface; `-1` indicates no VLAN tag is assigned	read only
bond-master-of	the UUID of the bond this PIF is the master of (if any)	read only
bond-slave-of	the UUID of the bond this PIF is the slave of (if any)	read only
management	is this PIF designated to be a management interface for the control domain	read only
network-uuid	the unique identifier/object reference of the virtual network to which this PIF is connected	read only
network-name-label	the name of the of the virtual network to which this PIF is connected	read only
host-uuid	the unique identifier/object reference of the XenServer host to which this PIF is connected	read only
host-name-label	the name of the XenServer host to which this PIF is connected	read only
IP-configuration-mode	type of network address configuration used; DHCP or static	read only
IP	IP address of the PIF, defined here if IP-configuration-mode is static; undefined if DHCP	read only
netmask	Netmask of the PIF, defined here if IP-configuration-mode is static; undefined if supplied by DHCP	read only
gateway	Gateway address of the PIF, defined here if IP-configuration-mode is static; undefined if supplied by DHCP	read only
DNS	DNS address of the PIF, defined here if IP-configuration-mode is static; undefined if supplied by DHCP	read only
io_read_kbs	average read rate in kB/s for the device	read only
io_write_kbs	average write rate in kB/s for the device	read only
carrier	link state for this device	read only
vendor-id	the ID assigned to NIC's vendor	read only
vendor-name	the NIC vendor's name	read only
device-id	the ID assigned by the vendor to this NIC model	read only
device-name	the name assigned by the vendor to this NIC model	read only
speed	data transfer rate of the NIC	read only
duplex	duplexing mode of the NIC; full or half	read only
pci-bus-path	PCI bus path address	read only
other-config:ethtool-speed	sets the speed of connection in Mbps	read write
other-config:ethtool-autoneg	set to `no` to disable autonegotiation of the physical interface or bridge. Default is `yes`.	read write
other-config:ethtool-duplex	Sets duplexing capability of the PIF, either `full` or `half`.	read write
other-config:ethtool-rx	set to `on` to enable receive checksum, `off` to disable	read write
other-config:ethtool-tx	set to `on` to enable transmit checksum, `off` to disable	read write
other-config:ethtool-sg	set to `on` to enable scatter gather, `off` to disable	read write
other-config:ethtool-tso	set to `on` to enable tcp segmentation offload, `off` to disable	read write
other-config:ethtool-ufo	set to `on` to enable udp fragment offload, `off` to disable	read write
other-config:ethtool-gso	set to `on` to enable generic segmentation offload, `off` to disable	read write
other-config:domain	comma-separated list used to set the DNS search path	read write
other-config:bond-miimon	interval between link liveness checks, in milliseconds	read write
other-config:bond-downdelay	number of milliseconds to wait after link is lost before really considering the link to have gone. This allows for transient link lossage	read write
other-config:bond-updelay	number of milliseconds to wait after the link comes up before really considering it up. Allows for links flapping up. Default is 31s to allow for time for switches to begin forwarding traffic.	read write
disallow-unplug	True if this PIF is a dedicated storage NIC, false otherwise	read/write

Note

Changes made to the other-config fields of a PIF will only take effect after a reboot. Alternately, use the xe pif-unplug and xe pif-plug commands to cause the PIF configuration to be rewritten.

8.4.11.1. pif-forget

pif-forget uuid=<uuid_of_pif>

Destroy the specified PIF object on a particular host.

8.4.11.2. pif-introduce

pif-introduce host-uuid=<UUID of XenServer host> mac=<mac_address_for_pif> device=<machine-readable name of the interface (for example, eth0)>

Create a new PIF object representing a physical interface on the specified XenServer host.

8.4.11.3. pif-plug

pif-plug uuid=<uuid_of_pif>

Attempt to bring up the specified physical interface.

8.4.11.4. pif-reconfigure-ip

pif-reconfigure-ip uuid=<uuid_of_pif> [ mode=<dhcp> | mode=<static> ]
gateway=<network_gateway_address> IP=<static_ip_for_this_pif>
netmask=<netmask_for_this_pif> [DNS=<dns_address>]

Modify the IP address of the PIF. For static IP configuration, set the mode parameter to static, with the gateway, IP, and netmask parameters set to the appropriate values. To use DHCP, set the mode parameter to DHCP and leave the static parameters undefined.

8.4.11.5. pif-scan

pif-scan host-uuid=<UUID of XenServer host>

Scan for new physical interfaces on a XenServer host.

8.4.11.6. pif-unplug

pif-unplug uuid=<uuid_of_pif>

Attempt to bring down the specified physical interface.

8.4.12. Pool commands

Commands for working with pools. A pool is an aggregate of one or more XenServer hosts. A pool uses one or more shared storage repositories so that the VMs running on one XenServer host in the pool can be migrated in near-real time (while still running, without needing to be shut down and brought back up) to another XenServer host in the pool. Each XenServer host is really a pool consisting of a single member by default. When a XenServer host is joined to a pool, it is designated as a member, and the pool it has joined becomes the master for the pool.

The singleton pool object can be listed with the standard object listing command (xe pool-list), and its parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

Pool parameters

Pools have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the pool	read only
name-label	the name of the pool	read/write
name-description	the description string of the pool	read/write
master	the unique identifier/object reference of XenServer host designated as the pool's master	read only
default-SR	the unique identifier/object reference of the default SR for the pool	read/write
crash-dump-SR	the unique identifier/object reference of the SR where any crash dumps for pool members are saved	read/write
suspend-image-SR	the unique identifier/object reference of the SR where suspended VMs on pool members are saved	read/write
other-config	a list of key/value pairs that specify additional configuration parameters for the pool	read/write map parameter
supported-sr-types	SR types that can be used by this pool	read only
ha-enabled	True if HA is enabled for the pool, false otherwise	read only
ha-configuration	reserved for future use.	read only
ha-statefiles	lists the UUIDs of the VDIs being used by HA to determine storage health	read only
ha-host-failures-to-tolerate	the number of host failures to tolerate before sending a system alert	read/write
ha-plan-exists-for	the number of hosts failures that can actually be handled, according to the calculations of the HA algorithm	read only
ha-allow-overcommit	`True` if the pool is allowed to be overcommitted, `False` otherwise	read/write
ha-overcommitted	`True` if the pool is currently overcommitted	read only
blobs	binary data store	read only
wlb-url	Path to the WLB server	read only
wlb-username	Name of the user of the WLB service	read only
wlb-enabled	True is WLB is enabled	read/write
wlb-verify-cert	True if there is a certificate to verify	read/write

8.4.12.1. pool-designate-new-master

pool-designate-new-master host-uuid=<UUID of member XenServer host to become new master>

Instruct the specified member XenServer host to become the master of an existing pool. This performs an orderly handover of the role of master host to another host in the resource pool. This command only works when the current master is online, and is not a replacement for the emergency mode commands listed below.

8.4.12.2. pool-dump-database

pool-dump-database file-name=<filename_to_dump_database_into_(on_client)>

Download a copy of the entire pool database and dump it into a file on the client.

8.4.12.3. pool-eject

pool-eject host-uuid=<UUID of XenServer host to eject>

Instruct the specified XenServer host to leave an existing pool.

8.4.12.4. pool-emergency-reset-master

pool-emergency-reset-master master-address=<address of the pool's master XenServer host>

Instruct a slave member XenServer host to reset its master address to the new value and attempt to connect to it. This command should not be run on master hosts.

8.4.12.5. pool-emergency-transition-to-master

pool-emergency-transition-to-master

Instruct a member XenServer host to become the pool master. This command is only accepted by the XenServer host if it has transitioned to emergency mode, meaning it is a member of a pool whose master has disappeared from the network and could not be contacted for some number of retries.

Note that this command may cause the password of the host to reset if it has been modified since joining the pool (see Section 8.4.18, “User commands”).

8.4.12.6. pool-ha-enable

pool-ha-enable heartbeat-sr-uuids=<SR_UUID_of_the_Heartbeat_SR>

Enable High Availability on the resource pool, using the specified SR UUID as the central storage heartbeat repository.

8.4.12.7. pool-ha-disable

pool-ha-disable

Disables the High Availability functionality on the resource pool.

8.4.12.8. pool-join

pool-join master-address=<address> master-username=<username> master-password=<password>

Instruct a XenServer host to join an existing pool.

8.4.12.9. pool-recover-slaves

pool-recover-slaves

Instruct the pool master to try and reset the master address of all members currently running in emergency mode. This is typically used after pool-emergency-transition-to-master has been used to set one of the members as the new master.

8.4.12.10. pool-restore-database

pool-restore-database file-name=<filename_to_restore_from_(on_client)> [dry-run=<true | false>]

Upload a database backup (created with pool-dump-database) to a pool. On receiving the upload, the master will restart itself with the new database.

There is also a dry run option, which allows you to check that the pool database can be restored without actually perform the operation. By default, dry-run is set to false.

8.4.12.11. pool-sync-database

pool-sync-database

Force the pool database to be synchronized across all hosts in the resource pool. This is not necessary in normal operation since the database is regularly automatically replicated, but can be useful for ensuring changes are rapidly replicated after performing a significant set of CLI operations.

8.4.13. Storage Manager commands

Commands for controlling Storage Manager plugins.

The storage manager objects can be listed with the standard object listing command (xe sm-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

SM parameters

SMs have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the SM plugin	read only
name-label	the name of the SM plugin	read only
name-description	the description string of the SM plugin	read only
type	the SR type that this plugin connects to	read only
vendor	name of the vendor who created this plugin	read only
copyright	copyright statement for this SM plugin	read only
required-api-version	minimum SM API version required on the XenServer host	read only
configuration	names and descriptions of device configuration keys	read only
capabilities	capabilities of the SM plugin	read only
driver-filename	the filename of the SR driver.	read only

8.4.14. SR commands

Commands for controlling SRs (storage repositories).

The SR objects can be listed with the standard object listing command (xe sr-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

SR parameters

SRs have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the SR	read only
name-label	the name of the SR	read/write
name-description	the description string of the SR	read/write
allowed-operations	list of the operations allowed on the SR in this state	read only set parameter
current-operations	list of the operations that are currently in progress on this SR	read only set parameter
VDIs	unique identifier/object reference for the virtual disks in this SR	read only set parameter
PBDs	unique identifier/object reference for the PBDs attached to this SR	read only set parameter
physical-utilisation	physical space currently utilized on this SR, in bytes. Note that for sparse disk formats, physical utilization may be less than virtual allocation	read only
physical-size	total physical size of the SR, in bytes	read only
type	type of the SR, used to specify the SR backend driver to use	read only
content-type	the type of the SR's content. Used to distinguish ISO libraries from other SRs. For storage repositories that store a library of ISOs, the `content-type` must be set to `iso`. In other cases, Citrix recommends that this be set either to empty, or the string `user`.	read only
shared	`True` if this SR is capable of being shared between multiple XenServer hosts; `False` otherwise	read/write
other-config	list of key/value pairs that specify additional configuration parameters for the SR .	read/write map parameter
host	The storage repository host name	read only
virtual-allocation	sum of virtual-size values of all VDIs in this storage repository (in bytes)	read only
sm-config	SM dependent data	read only map parameter
blobs	binary data store	read only

8.4.14.1. sr-create

sr-create name-label=<name> physical-size=<size> type=<type>
content-type=<content_type> device-config:<config_name>=<value>
[host-uuid=<XenServer host UUID>] [shared=<true | false>]

Creates an SR on the disk, introduces it into the database, and creates a PBD attaching the SR to a XenServer host. If shared is set to true, a PBD is created for each XenServer host in the pool; if shared is not specified or set to false, a PBD is created only for the XenServer host specified with host-uuid.

The exact device-config parameters differ depending on the device type. See Chapter 3, Storage for details of these parameters across the different storage backends.

8.4.14.2. sr-destroy

sr-destroy uuid=<sr_uuid>

Destroys the specified SR on the XenServer host.

8.4.14.3. sr-forget

sr-forget uuid=<sr_uuid>

The xapi agent forgets about a specified SR on the XenServer host, meaning that the SR is detached and you cannot access VDIs on it, but it remains intact on the source media (the data is not lost).

8.4.14.4. sr-introduce

sr-introduce name-label=<name>
physical-size=<physical_size>
type=<type>
content-type=<content_type>
uuid=<sr_uuid>

Just places an SR record into the database. The device-config parameters are specified by device-config:<parameter_key>=<parameter_value>, for example:

xe sr-introduce device-config:<device>=</dev/sdb1>

Note

This command is never used in normal operation. It is an advanced operation which might be useful if an SR needs to be reconfigured as shared after it was created, or to help recover from various failure scenarios.

8.4.14.5. sr-probe

sr-probe type=<type> [host-uuid=<uuid_of_host>] [device-config:<config_name>=<value>]

Performs a backend-specific scan, using the provided device-config keys. If the device-config is complete for the SR backend, then this will return a list of the SRs present on the device, if any. If the device-config parameters are only partial, then a backend-specific scan will be performed, returning results that will guide you in improving the remaining device-config parameters. The scan results are returned as backend-specific XML, printed out on the CLI.

The exact device-config parameters differ depending on the device type. See Chapter 3, Storage for details of these parameters across the different storage backends.

8.4.14.6. sr-scan

sr-scan uuid=<sr_uuid>

Force an SR scan, syncing the xapi database with VDIs present in the underlying storage substrate.

8.4.15. Task commands

Commands for working with long-running asynchronous tasks. These are tasks such as starting, stopping, and suspending a Virtual Machine, which are typically made up of a set of other atomic subtasks that together accomplish the requested operation.

The task objects can be listed with the standard object listing command (xe task-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

Task parameters

Tasks have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the Task	read only
name-label	the name of the Task	read only
name-description	the description string of the Task	read only
resident-on	the unique identifier/object reference of the host on which the task is running	read only
status	current status of the Task	read only
progress	if the Task is still pending, this field contains the estimated percentage complete, from 0. to 1. If the Task has completed, successfully or unsuccessfully, this should be 1.	read only
type	if the Task has successfully completed, this parameter contains the type of the encoded result - that is, the name of the class whose reference is in the result field; otherwise, this parameter's value is undefined	read only
result	if the Task has completed successfully, this field contains the result value, either Void or an object reference; otherwise, this parameter's value is undefined	read only
error_info	if the Task has failed, this parameter contains the set of associated error strings; otherwise, this parameter's value is undefined	read only
allowed_operations	list of the operations allowed in this state	read only
created	time the task has been created	read only
finished	time task finished (i.e. succeeded or failed). If task-status is pending, then the value of this field has no meaning	read only
subtask_of	contains the UUID of the tasks this task is a sub-task of	read only
subtasks	contains the UUID(s) of all the subtasks of this task	read only

8.4.15.1. task-cancel

task-cancel [uuid=<task_uuid>]

Direct the specified Task to cancel and return.

8.4.16. Template commands

Commands for working with VM templates.

Templates are essentially VMs with the is-a-template parameter set to true. A template is a "gold image" that contains all the various configuration settings to instantiate a specific VM. XenServer ships with a base set of templates, which range from generic "raw" VMs that can boot an OS vendor installation CD (RHEL, CentOS, SLES, Windows) to complete pre-configured OS instances (Debian Etch). With XenServer you can create VMs, configure them in standard forms for your particular needs, and save a copy of them as templates for future use in VM deployment.

The template objects can be listed with the standard object listing command (xe template-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

Template parameters

Templates have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the template	read only
name-label	the name of the template	read/write
name-description	the description string of the template	read/write
user-version	string for creators of VMs and templates to put version information	read/write
is-a-template	true if this is a template. Template VMs can never be started, they are used only for cloning other VMs Note that setting is-a-template using the CLI is not supported.	read/write
is-control-domain	true if this is a control domain (domain 0 or a driver domain)	read only
power-state	current power state; always `halted` for a template	read only
power-state	current power state; always `halted` for a template	read only
memory-dynamic-max	dynamic maximum memory in bytes. Currently unused, but if changed the following constraint must be obeyed: `memory_static_max` >= `memory_dynamic_max` >= `memory_dynamic_min` >= `memory_static_min`.	read/write
memory-dynamic-min	dynamic minimum memory in bytes. Currently unused, but if changed the same constraints for `memory-dynamic-max` must be obeyed.	read/write
memory-static-max	statically-set (absolute) maximum memory in bytes. This is the main value used to determine the amount of memory assigned to a VM.	read/write
memory-static-min	statically-set (absolute) minimum memory in bytes. This represents the absolute minimum memory, and `memory-static-min` must be less than `memory-static-max`. This value is currently unused in normal operation, but the previous constraint must be obeyed.	read/write
suspend-VDI-uuid	the VDI that a suspend image is stored on (has no meaning for a template)	read only
VCPUs-params	configuration parameters for the selected VCPU policy. You can tune a VCPU's pinning with xe vm-param-set \ uuid=<vm_uuid> \ VCPUs-params:mask=1,2,3 A VM created from this template will then run on physical CPUs 1, 2, and 3 only. You can also tune the VCPU priority (xen scheduling) with the cap and weight parameters; for example xe vm-param-set \ uuid=<vm_uuid> \ VCPUs-params:weight=512 xe vm-param-set \ uuid=<vm_uuid> \ VCPUs-params:cap=100 A VM based on this template with a weight of 512 will get twice as much CPU as a domain with a weight of 256 on a contended XenServer host. Legal weights range from 1 to 65535 and the default is 256. The cap optionally fixes the maximum amount of CPU a VM based on this template will be able to consume, even if the XenServer host has idle CPU cycles. The cap is expressed in percentage of one physical CPU: 100 is 1 physical CPU, 50 is half a CPU, 400 is 4 CPUs, etc. The default, 0, means there is no upper cap.	read/write map parameter
VCPUs-max	maximum number of VCPUs	read/write
VCPUs-at-startup	boot number of VCPUs	read/write
actions-after-crash	action to take if a VM based on this template crashes	read/write
console-uuids	virtual console devices	read only set parameter
platform	platform-specific configuration	read/write map parameter
allowed-operations	list of the operations allowed in this state	read only set parameter
current-operations	list of the operations that are currently in progress on this template	read only set parameter
allowed-VBD-devices	list of VBD identifiers available for use, represented by integers of the range `0`-`15`. This list is informational only, and other devices may be used (but may not work).	read only set parameter
allowed-VIF-devices	list of VIF identifiers available for use, represented by integers of the range `0`-`15`. This list is informational only, and other devices may be used (but may not work).	read only set parameter
HVM-boot-policy	the boot policy for HVM guests. Either `BIOS Order` or an empty string.	read/write
HVM-boot-params	the `order` key controls the HVM guest boot order, represented as a string where each character is a boot method: `d` for the CD/DVD, `c` for the root disk, and `n` for network PXE boot. The default is `dc`.	read/write map parameter
PV-kernel	path to the kernel	read/write
PV-ramdisk	path to the initrd	read/write
PV-args	string of kernel command line arguments	read/write
PV-legacy-args	string of arguments to make legacy VMs based on this template boot	read/write
PV-bootloader	name of or path to bootloader	read/write
PV-bootloader-args	string of miscellaneous arguments for the bootloader	read/write
last-boot-CPU-flags	describes the CPU flags on which a VM based on this template was last booted; not populated for a template	read only
resident-on	the XenServer host on which a VM based on this template is currently resident; appears as `<not in database>` for a template	read only
affinity	a XenServer host which a VM based on this template has preference for running on; used by the xe vm-start command to decide where to run the VM	read/write
other-config	list of key/value pairs that specify additional configuration parameters for the template	read/write map parameter
start-time	timestamp of the date and time that the metrics for a VM based on this template were read, in the form `yyyymmdd`T`hh:mm:ss` `z`, where `z` is the single-letter military timezone indicator, for example, Z for UTC (GMT); set to 1 Jan 1970 Z (beginning of Unix/POSIX epoch) for a template	read only
install-time	timestamp of the date and time that the metrics for a VM based on this template were read, in the form `yyyymmdd`T`hh:mm:ss` `z`, where `z` is the single-letter military timezone indicator, for example, Z for UTC (GMT); set to 1 Jan 1970 Z (beginning of Unix/POSIX epoch) for a template	read only
memory-actual	the actual memory being used by a VM based on this template; `0` for a template	read only
VCPUs-number	the number of virtual CPUs assigned to a VM based on this template; `0` for a template	read only
VCPUs-utilisation	list of virtual CPUs and their weight	read only map parameter
os-version	the version of the operating system for a VM based on this template; appears as `<not in database>` for a template	read only map parameter
PV-drivers-version	the versions of the paravirtualized drivers for a VM based on this template; appears as `<not in database>` for a template	read only map parameter
PV-drivers-up-to-date	flag for latest version of the paravirtualized drivers for a VM based on this template; appears as `<not in database>` for a template	read only
memory	memory metrics reported by the agent on a VM based on this template; appears as `<not in database>` for a template	read only map parameter
disks	disk metrics reported by the agent on a VM based on this template; appears as `<not in database>` for a template	read only map parameter
networks	network metrics reported by the agent on a VM based on this template; appears as `<not in database>` for a template	read only map parameter
other	other metrics reported by the agent on a VM based on this template; appears as `<not in database>` for a template	read only map parameter
guest-metrics-last-updated	timestamp when the last write to these fields was performed by the in-guest agent, in the form `yyyymmdd`T`hh:mm:ss` `z`, where `z` is the single-letter military timezone indicator, for example, Z for UTC (GMT)	read only
actions-after-shutdown	action to take after the VM has shutdown	read/write
actions-after-reboot	action to take after the VM has rebooted	read/write
possible-hosts	list of hosts that could potentially host the VM	read only
HVM-shadow-multiplier	multiplier applied to the amount of shadow that will be made available to the guest	read/write
dom-id	domain ID (if available, `-1` otherwise)	read only
recommendations	XML specification of recommended values and ranges for properties of this VM	read only
xenstore-data	data to be inserted into the xenstore tree (/local/domain/<domid>/vm-data) after the VM is created.	read/write map parameter
is-a-snapshot	True if this template is a VM snapshot	read only
snapshot_of	the UUID of the VM that this template is a snapshot of	read only
snapshots	the UUID(s) of any snapshots that have been taken of this template	read only
snapshot_time	the timestamp of the most recent VM snapshot taken	read only
memory-target	the target amount of memory set for this template	read only
blocked-operations	lists the operations that cannot be performed on this template	read/write map parameter
last-boot-record	record of the last boot parameters for this template, in XML format	read only
ha-always-run	`True` if an instance of this template will always restarted on another host in case of the failure of the host it is resident on	read/write
ha-restart-priority	1, 2, 3 or best effort. 1 is the highest restart priority	read/write
blobs	binary data store	read only
live	only relevant to a running VM.	read only

8.4.16.1. template-export

template-export template-uuid=<uuid_of_existing_template> filename=<filename_for_new_template>

Exports a copy of a specified template to a file with the specified new filename.

8.4.17. Update commands

Commands for working with updates to the OEM edition of XenServer. For commands relating to updating the standard non-OEM editions of XenServer, see Section 8.4.9, “Patch (update) commands” for details.

8.4.17.1. update-upload

update-upload file-name=<name_of_upload_file>

Streams a new software image to a OEM edition XenServer host. You must then restart the host for this to take effect.

8.4.18. User commands

8.4.18.1. user-password-change

user-password-change old=<old_password> new=<new_password>

Changes the password of the logged-in user. The old password field is not checked because you require supervisor privilege to make this call.

8.4.19. VBD commands

Commands for working with VBDs (Virtual Block Devices).

A VBD is a software object that connects a VM to the VDI, which represents the contents of the virtual disk. The VBD has the attributes which tie the VDI to the VM (is it bootable, its read/write metrics, and so on), while the VDI has the information on the physical attributes of the virtual disk (which type of SR, whether the disk is shareable, whether the media is read/write or read only, and so on).

The VBD objects can be listed with the standard object listing command (xe vbd-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

VBD parameters

VBDs have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the VBD	read only
vm-uuid	the unique identifier/object reference for the VM this VBD is attached to	read only
vm-name-label	the name of the VM this VBD is attached to	read only
vdi-uuid	the unique identifier/object reference for the VDI this VBD is mapped to	read only
vdi-name-label	the name of the VDI this VBD is mapped to	read only
empty	if true, this represents an empty drive	read only
device	the device seen by the guest, for example `hda1`	read only
userdevice	user-friendly device name	read/write
bootable	true if this VBD is bootable	read/write
mode	the mode the VBD should be mounted with	read/write
type	how the VBD appears to the VM, for example disk or CD	read/write
currently-attached	`True` if the VBD is currently attached on this host, `false` otherwise	read only
storage-lock	`True` if a storage-level lock was acquired	read only
status-code	error/success code associated with the last attach operation	read only
status-detail	error/success information associated with the last attach operation status	read only
qos_algorithm_type	the QoS algorithm to use	read/write
qos_algorithm_params	parameters for the chosen QoS algorithm	read/write map parameter
qos_supported_algorithms	supported QoS algorithms for this VBD	read only set parameter
io_read_kbs	average read rate in kB per second for this VBD	read only
io_write_kbs	average write rate in kB per second for this VBD	read only
allowed-operations	list of the operations allowed in this state. This list is advisory only and the server state may have changed by the time this field is read by a client.	read only set parameter
current-operations	links each of the running tasks using this object (by reference) to a current_operation enum which describes the nature of the task.	read only set parameter
unpluggable	true if this VBD will support hot-unplug	read/write
attachable	`True` if the device can be attached	read only
other-config	additional configuration	read/write map parameter

8.4.19.1. vbd-create

vbd-create vm-uuid=<uuid_of_the_vm> device=<device_value>
vdi-uuid=<uuid_of_the_vdi_the_vbd_will_connect_to> [bootable=true] [type=<Disk | CD>] [mode=<RW | RO>]

Create a new VBD on a VM.

Appropriate values for the device field are listed in the parameter allowed-VBD-devices on the specified VM. Before any VBDs exist there, the allowable values are integers from 0-15.

If the type is Disk, vdi-uuid is required. Mode can be RO or RW for a Disk.

If the type is CD, vdi-uuid is optional; if no VDI is specified, an empty VBD will be created for the CD. Mode must be RO for a CD.

8.4.19.2. vbd-destroy

vbd-destroy uuid=<uuid_of_vbd>

Destroy the specified VBD.

If the VBD has its other-config:owner parameter set to true, the associated VDI will also be destroyed.

8.4.19.3. vbd-eject

vbd-eject uuid=<uuid_of_vbd>

Remove the media from the drive represented by a VBD. This command only works if the media is of a removable type (a physical CD or an ISO); otherwise an error message VBD_NOT_REMOVABLE_MEDIA is returned.

8.4.19.4. vbd-insert

vbd-insert uuid=<uuid_of_vbd> vdi-uuid=<uuid_of_vdi_containing_media>

Insert new media into the drive represented by a VBD. This command only works if the media is of a removable type (a physical CD or an ISO); otherwise an error message VBD_NOT_REMOVABLE_MEDIA is returned.

8.4.19.5. vbd-plug

vbd-plug uuid=<uuid_of_vbd>

Attempt to attach the VBD while the VM is in the running state.

8.4.19.6. vbd-unplug

vbd-unplug uuid=<uuid_of_vbd>

Attempts to detach the VBD from the VM while it is in the running state.

8.4.20. VDI commands

Commands for working with VDIs (Virtual Disk Images).

A VDI is a software object that represents the contents of the virtual disk seen by a VM, as opposed to the VBD, which is a connector object that ties a VM to the VDI. The VDI has the information on the physical attributes of the virtual disk (which type of SR, whether the disk is shareable, whether the media is read/write or read only, and so on), while the VBD has the attributes which tie the VDI to the VM (is it bootable, its read/write metrics, and so on).

The VDI objects can be listed with the standard object listing command (xe vdi-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

VDI parameters

VDIs have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the VDI	read only
name-label	the name of the VDI	read/write
name-description	the description string of the VDI	read/write
allowed-operations	a list of the operations allowed in this state	read only set parameter
current-operations	a list of the operations that are currently in progress on this VDI	read only set parameter
sr-uuid	SR in which the VDI resides	read only
vbd-uuids	a list of VBDs that refer to this VDI	read only set parameter
crashdump-uuids	list of crash dumps that refer to this VDI	read only set parameter
virtual-size	size of disk as presented to the VM, in bytes. Note that, depending on the storage backend type, the size may not be respected exactly	read only
physical-utilisation	amount of physical space that the VDI is currently taking up on the SR, in bytes	read only
type	type of VDI, for example, System or User	read only
sharable	true if this VDI may be shared	read only
read-only	true if this VDI can only be mounted read-only	read only
storage-lock	true if this VDI is locked at the storage level	read only
parent	references the parent VDI, if this VDI is part of a chain	read only
missing	true if SR scan operation reported this VDI as not present	read only
other-config	additional configuration information for this VDI	read/write map parameter
sr-name-label	name of the containing storage repository	read only
location	location information	read only
managed	true if the VDI is managed	read only
xenstore-data	data to be inserted into the xenstore tree (`/local/domain/0/backend/vbd/<domid>/<device-id>/sm-data`) after the VDI is attached. This is generally set by the SM backends on vdi_attach.	read only map parameter
sm-config	SM dependent data	read only map parameter
is-a-snapshot	`True` if this VDI is a VM storage snapshot	read only
snapshot_of	the UUID of the storage this VDI is a snapshot of	read only
snapshots	the UUID(s) of all snapshots of this VDI	read only
snapshot_time	the timestamp of the snapshot operation that created this VDI	read only

8.4.20.1. vdi-clone

vdi-clone uuid=<uuid_of_the_vdi> [driver-params:<key=value>]

Create a new, writable copy of the specified VDI that can be used directly. It is a variant of vdi-copy that is capable of exposing high-speed image clone facilities where they exist.

The optional driver-params map parameter can be used for passing extra vendor-specific configuration information to the back end storage driver that the VDI is based on. See the storage vendor driver documentation for details.

8.4.20.2. vdi-copy

vdi-copy uuid=<uuid_of_the_vdi> sr-uuid=<uuid_of_the_destination_sr>

Copy a VDI to a specified SR.

8.4.20.3. vdi-create

vdi-create sr-uuid=<uuid_of_the_sr_where_you_want_to_create_the_vdi>
name-label=<name_for_the_vdi>
type=<system | user | suspend | crashdump>
virtual-size=<size_of_virtual_disk>
sm-config-*=<storage_specific_configuration_data>

Create a VDI.

The virtual-size parameter can be specified in bytes or using the IEC standard suffixes KiB (2¹⁰ bytes), MiB (2²⁰ bytes), GiB (2³⁰ bytes), and TiB (2⁴⁰ bytes).

Note

SR types that support sparse allocation of disks (such as Local VHD and NFS) do not enforce virtual allocation of disks. Users should therefore take great care when over-allocating virtual disk space on an SR. If an over-allocated SR does become full, disk space must be made available either on the SR target substrate or by deleting unused VDIs in the SR.

Note

Some SR types might round up the virtual-size value to make it divisible by a configured block size.

8.4.20.4. vdi-destroy

vdi-destroy uuid=<uuid_of_vdi>

Destroy the specified VDI.

Note

In the case of Local VHD and NFS SR types, disk space is not immediately released on vdi-destroy, but periodically during a storage repository scan operation. Users that need to force deleted disk space to be made available should call sr-scan manually.

8.4.20.5. vdi-forget

vdi-forget uuid=<uuid_of_vdi>

Unconditionally removes a VDI record from the database without touching the storage backend. In normal operation, you should be using vdi-destroy instead.

8.4.20.6. vdi-import

vdi-import uuid=<uuid_of_vdi> filename=<filename_of_raw_vdi>

Import a raw VDI.

8.4.20.7. vdi-introduce

vdi-introduce uuid=<uuid_of_vdi>
sr-uuid=<uuid_of_sr_to_import_into>
name-label=<name_of_the_new_vdi>
type=<system | user | suspend | crashdump>
location=<device_location_(varies_by_storage_type)>
[name-description=<description_of_vdi>]
[sharable=<yes | no>]
[read-only=<yes | no>]
[other-config=<map_to_store_misc_user_specific_data>]
[xenstore-data=<map_to_of_additional_xenstore_keys>]
[sm-config<storage_specific_configuration_data>]

Create a VDI object representing an existing storage device, without actually modifying or creating any storage. This command is primarily used internally to automatically introduce hot-plugged storage devices.

8.4.20.8. vdi-resize

vdi-resize uuid=<vdi_uuid> disk-size=<new_size_for_disk>

Resize the VDI specified by UUID.

8.4.20.9. vdi-snapshot

vdi-snapshot uuid=<uuid_of_the_vdi> [driver-params=<params>]

Produces a read-write version of a VDI that can be used as a reference for backup and/or templating purposes. You can perform a backup from a snapshot rather than installing and running backup software inside the VM. The VM can continue running while external backup software streams the contents of the snapshot to the backup media. Similarly, a snapshot can be used as a "gold image" on which to base a template. A template can be made using any VDIs.

A clone of a snapshot should always produce a writable VDI.

8.4.20.10. vdi-unlock

vdi-unlock uuid=<uuid_of_vdi_to_unlock> [force=true]

Attempts to unlock the specified VDIs. If force=true is passed to the command, it will force the unlocking operation.

8.4.21. VIF commands

Commands for working with VIFs (Virtual network interfaces).

The VIF objects can be listed with the standard object listing command (xe vif-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

VIF parameters

VIFs have the following parameters:

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the VIF	read only
vm-uuid	the unique identifier/object reference for the VM that this VIF resides on	read only
vm-name-label	the name of the VM that this VIF resides on	read only
allowed-operations	a list of the operations allowed in this state	read only set parameter
current-operations	a list of the operations that are currently in progress on this VIF	read only set parameter
device	integer label of this VIF, indicating the order in which VIF backends were created	read only
MAC	MAC address of VIF, as exposed to the VM	read only
MTU	Maximum Transmission Unit of the VIF in bytes. This parameter is read-only, but you can override the MTU setting with the `mtu` key using the other-config `map` parameter. For example, to reset the MTU on a virtual NIC to use jumbo frames: xe vif-param-set \ uuid=<vif_uuid> \ other-config:mtu=9000	read only
currently-attached	true if the device is currently attached	read only
qos_algorithm_type	QoS algorithm to use	read/write
qos_algorithm_params	parameters for the chosen QoS algorithm	read/write map parameter
qos_supported_algorithms	supported QoS algorithms for this VIF	read only set parameter
MAC-autogenerated	True if the MAC address of the VIF was automatically generated	read only
other-config	Additional configuration key:value pairs	read/write map parameter
other-config:ethtool-rx	set to `on` to enable receive checksum, `off` to disable	read write
other-config:ethtool-tx	set to `on` to enable transmit checksum, `off` to disable	read write
other-config:ethtool-sg	set to `on` to enable scatter gather, `off` to disable	read write
other-config:ethtool-tso	set to `on` to enable tcp segmentation offload, `off` to disable	read write
other-config:ethtool-ufo	set to `on` to enable udp fragment offload, `off` to disable	read write
other-config:ethtool-gso	set to `on` to enable generic segmentation offload, `off` to disable	read write
other-config:promiscuous	`true` to a VIF to be promiscuous on the bridge, so that it sees all traffic over the bridge. Useful for running an Intrusion Detection System (IDS) or similar in a VM.	read write
network-uuid	the unique identifier/object reference of the virtual network to which this VIF is connected	read only
network-name-label	the descriptive name of the virtual network to which this VIF is connected	read only
io_read_kbs	average read rate in kB/s for this VIF	read only
io_write_kbs	average write rate in kB/s for this VIF	read only

8.4.21.1. vif-create

vif-create vm-uuid=<uuid_of_the_vm> device=<see below>
network-uuid=<uuid_of_the_network_the_vif_will_connect_to> [mac=<mac_address>]

Create a new VIF on a VM.

Appropriate values for the device field are listed in the parameter allowed-VIF-devices on the specified VM. Before any VIFs exist there, the allowable values are integers from 0-15.

The mac parameter is the standard MAC address in the form aa:bb:cc:dd:ee:ff. If you leave it unspecified, an appropriate random MAC address will be created. You can also explicitly set a random MAC address by specifying mac=random.

8.4.21.2. vif-destroy

vif-destroy uuid=<uuid_of_vif>

Destroy a VIF.

8.4.21.3. vif-plug

vif-plug uuid=<uuid_of_vif>

Attempt to attach the VIF while the VM is in the running state.

8.4.21.4. vif-unplug

vif-unplug uuid=<uuid_of_vif>

Attempts to detach the VIF from the VM while it is running.

8.4.22. VLAN commands

Commands for working with VLANs (virtual networks). To list and edit virtual interfaces, refer to the PIF commands, which have a VLAN parameter to signal that they have an associated virtual network (see Section 8.4.11, “PIF commands”). For example, to list VLANs you need to use xe pif-list.

8.4.22.1. vlan-create

vlan-create pif-uuid=<uuid_of_pif> vlan=<vlan_number> network-uuid=<uuid_of_network>

Create a new VLAN on a XenServer host.

8.4.22.2. pool-vlan-create

vlan-create pif-uuid=<uuid_of_pif> vlan=<vlan_number> network-uuid=<uuid_of_network>

Create a new VLAN on all hosts on a pool, by determining which interface (for example, eth0) the specified network is on on each host and creating and plugging a new PIF object one each host accordingly.

8.4.22.3. vlan-destroy

vlan-destroy uuid=<uuid_of_pif_mapped_to_vlan>

Destroy a VLAN. Requires the UUID of the PIF that represents the VLAN.

8.4.23. VM commands

Commands for controlling VMs and their attributes.

VM selectors

Several of the commands listed here have a common mechanism for selecting one or more VMs on which to perform the operation. The simplest way is by supplying the argument vm=<name_or_uuid>. VMs can also be specified by filtering the full list of VMs on the values of fields. For example, specifying power-state=halted will select all VMs whose power-state parameter is equal to halted. Where multiple VMs are matching, the option --multiple must be specified to perform the operation. The full list of parameters that can be matched is described at the beginning of this section, and can be obtained by the command xe vm-list params=all. If no parameters to select VMs are given, the operation will be performed on all VMs.

The VM objects can be listed with the standard object listing command (xe vm-list), and the parameters manipulated with the standard parameter commands. See Section 8.3.2, “Low-level param commands” for details.

VM parameters

VMs have the following parameters:

Note

All writeable VM parameter values can be changed while the VM is running, but the new parameters are not applied dynamically and will not be applied until the VM is rebooted.

Parameter Name	Description	Type
uuid	the unique identifier/object reference for the VM	read only
name-label	the name of the VM	read/write
name-description	the description string of the VM	read/write
user-version	string for creators of VMs and templates to put version information	read/write
is-a-template	`False` unless this is a template; template VMs can never be started, they are used only for cloning other VMs Note that setting `is-a-template` using the CLI is not supported.	read/write
is-control-domain	`True` if this is a control domain (domain 0 or a driver domain)	read only
power-state	current power state	read only
memory-dynamic-max	dynamic maximum in bytes	read/write
memory-dynamic-min	dynamic minimum in bytes	read/write
memory-static-max	statically-set (absolute) maximum in bytes. If you want to change this value, the VM must be shut down.	read/write
memory-static-min	statically-set (absolute) minimum in bytes. If you want to change this value, the VM must be shut down.	read/write
suspend-VDI-uuid	the VDI that a suspend image is stored on	read only
VCPUs-params	configuration parameters for the selected VCPU policy. You can tune a VCPU's pinning with xe vm-param-set \ uuid=<vm_uuid> \ VCPUs-params:mask=1,2,3 The selected VM will then run on physical CPUs 1, 2, and 3 only. You can also tune the VCPU priority (xen scheduling) with the cap and weight parameters; for example xe vm-param-set \ uuid=<template_uuid> \ VCPUs-params:weight=512 xe vm-param-set \ uuid=<template UUID> \ VCPUs-params:cap=100 A VM with a weight of 512 will get twice as much CPU as a domain with a weight of 256 on a contended XenServer host. Legal weights range from 1 to 65535 and the default is 256. The cap optionally fixes the maximum amount of CPU a VM will be able to consume, even if the XenServer host has idle CPU cycles. The cap is expressed in percentage of one physical CPU: 100 is 1 physical CPU, 50 is half a CPU, 400 is 4 CPUs, etc. The default, 0, means there is no upper cap.	read/write map parameter
VCPUs-max	maximum number of virtual CPUs.	read/write
VCPUs-at-startup	boot number of virtual CPUs	read/write
actions-after-crash	action to take if the VM crashes. For PV guests, valid parameters are: preserve (for analysis only), coredump_and_restart (record a coredump and reboot VM), coredump_and_destroy (record a coredump and leave VM halted), restart (no coredump and restart VM), and destroy (no coredump and leave VM halted).	read/write
console-uuids	virtual console devices	read only set parameter
platform	platform-specific configuration	read/write map parameter
allowed-operations	list of the operations allowed in this state	read only set parameter
current-operations	a list of the operations that are currently in progress on the VM	read only set parameter
allowed-VBD-devices	list of VBD identifiers available for use, represented by integers of the range `0`-`15`. This list is informational only, and other devices may be used (but may not work).	read only set parameter
allowed-VIF-devices	list of VIF identifiers available for use, represented by integers of the range `0`-`15`. This list is informational only, and other devices may be used (but may not work).	read only set parameter
HVM-boot-policy	the boot policy for HVM guests. Either `BIOS Order` or an empty string.	read/write
HVM-boot-params	the `order` key controls the HVM guest boot order, represented as a string where each character is a boot method: `d` for the CD/DVD, `c` for the root disk, and `n` for network PXE boot. The default is `dc`.	read/write map parameter
HVM-shadow-multiplier	Floating point value which controls the amount of shadow memory overhead to grant the VM. Defaults to `1.0` (the minimum value), and should only be changed by advanced users.	read/write
PV-kernel	path to the kernel	read/write
PV-ramdisk	path to the initrd	read/write
PV-args	string of kernel command line arguments	read/write
PV-legacy-args	string of arguments to make legacy VMs boot	read/write
PV-bootloader	name of or path to bootloader	read/write
PV-bootloader-args	string of miscellaneous arguments for the bootloader	read/write
last-boot-CPU-flags	describes the CPU flags on which the VM was last booted	read only
resident-on	the XenServer host on which a VM is currently resident	read only
affinity	a XenServer host which the VM has preference for running on; used by the xe vm-start command to decide where to run the VM	read/write
other-config	A list of key/value pairs that specify additional configuration parameters for the VM For example, a VM will be started automatically after host boot if the other-config parameter includes the key/value pair auto_poweron: true	read/write map parameter
start-time	timestamp of the date and time that the metrics for the VM were read, in the form `yyyymmdd`T`hh:mm:ss` `z`, where `z` is the single-letter military timezone indicator, for example, Z for UTC (GMT)	read only
install-time	timestamp of the date and time that the metrics for the VM were read, in the form `yyyymmdd`T`hh:mm:ss` `z`, where `z` is the single-letter military timezone indicator, for example, Z for UTC (GMT)	read only
memory-actual	the actual memory being used by a VM	read only
VCPUs-number	the number of virtual CPUs assigned to the VM For a paravirtualized Linux VM, this number can differ from `VCPUS-max` and can be changed without rebooting the VM using the vm-vcpu-hotplug command. See Section 8.4.23.30, “vm-vcpu-hotplug”. Windows VMs always run with the number of vCPUs set to `VCPUs-max` and must be rebooted to change this value. Note that performance will drop sharply if you set `VCPUs-number` to a value greater than the number of physical CPUs on the XenServer host.	read only
VCPUs-utilisation	a list of virtual CPUs and their weight	read only map parameter
os-version	the version of the operating system for the VM	read only map parameter
PV-drivers-version	the versions of the paravirtualized drivers for the VM	read only map parameter
PV-drivers-up-to-date	flag for latest version of the paravirtualized drivers for the VM	read only
memory	memory metrics reported by the agent on the VM	read only map parameter
disks	disk metrics reported by the agent on the VM	read only map parameter
networks	network metrics reported by the agent on the VM	read only map parameter
other	other metrics reported by the agent on the VM	read only map parameter
guest-metrics-last-updated	timestamp when the last write to these fields was performed by the in-guest agent, in the form `yyyymmdd`T`hh:mm:ss` `z`, where `z` is the single-letter military timezone indicator, for example, Z for UTC (GMT)	read only
actions-after-shutdown	action to take after the VM has shutdown	read/write
actions-after-reboot	action to take after the VM has rebooted	read/write
possible-hosts	potential hosts of this VM	read only
dom-id	domain ID (if available, -1 otherwise)	read only
recommendations	XML specification of recommended values and ranges for properties of this VM	read only
xenstore-data	data to be inserted into the xenstore tree (`/local/domain/<domid>/vm-data`) after the VM is created	read/write map parameter
is-a-snapshot	`True` if this VM is a snapshot	read only
snapshot_of	the UUID of the VM this is a snapshot of	read only
snapshots	the UUID(s) of all snapshots of this VM	read only
snapshot_time	the timestamp of the snapshot operation that created this VM snapshot	read only
memory-target	the target amount of memory set for this VM	read only
blocked-operations	lists the operations that cannot be performed on this VM	read/write map parameter
last-boot-record	record of the last boot parameters for this template, in XML format	read only
ha-always-run	`True` if this VM will always restarted on another host in case of the failure of the host it is resident on	read/write
ha-restart-priority	1, 2, 3 or best effort. 1 is the highest restart priority	read/write
blobs	binary data store	read only
live	`True` if the VM is running, false if HA suspects that the VM may not be running.	read only

8.4.23.1. vm-cd-add

vm-cd-add cd-name=<name_of_new_cd> device=<integer_value_of_an_available_vbd>
[<vm-selector>=<vm_selector_value>...]

Add a new virtual CD to the selected VM. The device parameter should be selected from the value of the allowed-VBD-devices parameter of the VM.

The VM or VMs on which this operation should be performed are selected using the standard selection mechanism (see VM selectors). Optional arguments can be any number of the VM parameters listed at the beginning of this section.

8.4.23.2. vm-cd-eject

vm-cd-eject [<vm-selector>=<vm_selector_value>...]

Eject a CD from the virtual CD drive. This command will only work if there is one and only one CD attached to the VM. When there are two or more CDs, please use the command xe vbd-eject and specify the UUID of the VBD.

8.4.23.3. vm-cd-insert

vm-cd-insert cd-name=<name_of_cd> [<vm-selector>=<vm_selector_value>...]

Insert a CD into the virtual CD drive. This command will only work if there is one and only one empty CD device attached to the VM. When there are two or more empty CD devices, please use the command xe vbd-insert and specify the UUIDs of the VBD and of the VDI to insert.

8.4.23.4. vm-cd-list

vm-cd-list [vbd-params] [vdi-params] [<vm-selector>=<vm_selector_value>...]

Lists CDs attached to the specified VMs.

You can also select which VBD and VDI parameters to list.

8.4.23.5. vm-cd-remove

vm-cd-remove cd-name=<name_of_cd> [<vm-selector>=<vm_selector_value>...]

Remove a virtual CD from the specified VMs.

8.4.23.6. vm-clone

vm-clone new-name-label=<name_for_clone>
[new-name-description=<description_for_clone>] [<vm-selector>=<vm_selector_value>...]

Clone an existing VM, using storage-level fast disk clone operation where available. Specify the name and the optional description for the resulting cloned VM using the new-name-label and new-name-description arguments.

8.4.23.7. vm-compute-maximum-memory

vm-compute-maximum-memory total=<amount_of_available_physical_ram_in_bytes>
[approximate=<add overhead memory for additional vCPUS? true | false>]
[<vm_selector>=<vm_selector_value>...]

Calculate the maximum amount of static memory which can be allocated to an existing VM, using the total amount of physical RAM as an upper bound. The optional parameter approximate reserves sufficient extra memory in the calculation to account for adding extra vCPUs into the VM at a later date.

For example:

xe vm-compute-maximum-memory vm=testvm total=`xe host-list params=memory-free --minimal`

uses the value of the memory-free parameter returned by the xe host-list command to set the maximum memory of the VM named testvm.

The VM or VMs on which this operation will be performed are selected using the standard selection mechanism (see VM selectors). Optional arguments can be any number of the VM parameters listed at the beginning of this section.

8.4.23.8. vm-copy

vm-copy new-name-label=<name_for_copy> [new-name-description=<description_for_copy>]
[sr-uuid=<uuid_of_sr>] [<vm-selector>=<vm_selector_value>...]

Copy an existing VM, but without using storage-level fast disk clone operation (even if this is available). The disk images of the copied VM are guaranteed to be "full images" - that is, not part of a copy-on-write (CoW) chain.

Specify the name and the optional description for the resulting copied VM using the new-name-label and new-name-description arguments.

Specify the destination SR for the resulting copied VM using the sr-uuid. If this parameter is not specified, the destination is the same SR that the original VM is in.

8.4.23.9. vm-crashdump-list

vm-crashdump-list [<vm-selector>=<vm selector value>...]

List crashdumps associated with the specified VMs.

8.4.23.10. vm-data-source-forget

vm-data-source-forget data-source=<name_description_of_data-source> [<vm-selector>=<vm selector value>...]

Stop recording the specified data source for a VM, and forget all of the recorded data.

8.4.23.11. vm-data-source-list

vm-data-source-list [<vm-selector>=<vm selector value>...]

List the data sources that can be recorded for a VM.

8.4.23.12. vm-data-source-query

vm-data-source-query data-source=<name_description_of_data-source> [<vm-selector>=<vm selector value>...]

Display the specified data source for a VM.

8.4.23.13. vm-data-source-record

vm-data-source-record data-source=<name_description_of_data-source> [<vm-selector>=<vm selector value>...]

Record the specified data source for a VM.

This will write the information from the data source to the VM's persistent performance metrics database. This database is distinct from the normal agent database for performance reasons.

Data sources have the true/false parameters standard and enabled, which can be seen in the output of the vm-data-source-list command. If enabled=true, the data source's metrics are currently being recorded to the performance database; if enabled=false they are not. Data sources with standard=true have enabled=true and have their metrics recorded to the performance database by default. Data sources which have standard=false have enabled=false by default. The vm-data-source-record command sets enabled=false.

Once enabled, you can stop recording the data source's metrics using the vm-data-source-forget command.

8.4.23.14. vm-destroy

vm-destroy uuid=<uuid_of_vm>

Destroy the specified VM. This leaves the storage associated with the VM intact. To delete storage as well, use xe vm-uninstall.

8.4.23.15. vm-disk-add

vm-disk-add disk-size=<size_of_disk_to_add> device=<uuid_of_device>
[<vm-selector>=<vm_selector_value>...]

Add a new disk to the specified VMs. Select the device parameter from the value of the allowed-VBD-devices parameter of the VMs.

The disk-size parameter can be specified in bytes or using the IEC standard suffixes KiB (2¹⁰ bytes), MiB (2²⁰ bytes), GiB (2³⁰ bytes), and TiB (2⁴⁰ bytes).

8.4.23.16. vm-disk-list

vm-disk-list [vbd-params] [vdi-params] [<vm-selector>=<vm_selector_value>...]

Lists disks attached to the specified VMs. The vbd-params and vdi-params parameters control the fields of the respective objects to output and should be given as a comma-separated list, or the special key all for the complete list.

8.4.23.17. vm-disk-remove

vm-disk-remove device=<integer_label_of_disk> [<vm-selector>=<vm_selector_value>...]

Remove a disk from the specified VMs and destroy it.

8.4.23.18. vm-export

vm-export filename=<export_filename>
[metadata=<true | false>]
[<vm-selector>=<vm_selector_value>...]

Export the specified VMs (including disk images) to a file on the local machine. Specify the filename to export the VM into using the filename parameter. By convention, the filename should have a .xva extension.

If the metadata parameter is true, then the disks are not exported, and only the VM metadata is written to the output file. This is intended to be used when the underlying storage is transferred through other mechanisms, and permits the VM information to be recreated (see Section 8.4.23.19, “vm-import”).

8.4.23.19. vm-import

vm-import filename=<export_filename>
[metadata=<true | false>]
[preserve=<true | false>]
[sr-uuid=<destination_sr_uuid>]

Import a VM from a previously-exported file. If preserve is set to true, the MAC address of the original VM will be preserved. The sr-uuid determines the destination SR to import the VM into, and is the default SR if not specified.

The filename parameter can also point to an XVA-format VM, which is the legacy export format from XenServer 3.2 and is used by some third-party vendors to provide virtual appliances. This format uses a directory to store the VM data, so set filename to the root directory of the XVA export and not an actual file. Subsequent exports of the imported legacy guest will automatically be upgraded to the new filename-based format, which stores much more data about the configuration of the VM.

Note

The older directory-based XVA format does not fully preserve all the VM attributes. In particular, imported VMs will not have any virtual network interfaces attached by default. If networking is required, create one using vif-create and vif-plug.

If the metadata is true, then a previously exported set of metadata can be imported without their associated disk blocks. Metadata-only import will fail if any VDIs cannot be found (named by SR and VDI.location) unless the --force option is specified, in which case the import will proceed regardless. If disks can be mirrored or moved out-of-band then metadata import/export represents a fast way of moving VMs between disjoint pools (e.g. as part of a disaster recovery plan).

Note

Multiple VM imports will be performed faster in serial that in parallel.

8.4.23.20. vm-install

vm-install new-name-label=<name>
[ template-uuid=<uuid_of_desired_template> | [template=<uuid_or_name_of_desired_template>]]
[ sr-uuid=<sr_uuid> | sr-name-label=<name_of_sr> ]

Install a VM from a template. Specify the template name using either the template-uuid or template argument. Specify an SR other than the default SR using either the sr-uuid or sr-name-label argument.

8.4.23.21. vm-memory-shadow-multiplier-set

vm-memory-shadow-multiplier-set [<vm-selector>=<vm_selector_value>...]
[multiplier=<float_memory_multiplier>]

Set the shadow memory multiplier for the specified VM.

This is an advanced option which modifies the amount of shadow memory assigned to a hardware-assisted VM. In some specialized application workloads, such as Citrix XenApp, extra shadow memory is required to achieve full performance.

This memory is considered to be an overhead. It is separated from the normal memory calculations for accounting memory to a VM. When this command is invoked, the amount of free XenServer host memory will decrease according to the multiplier, and the HVM_shadow_multiplier field will be updated with the actual value which Xen has assigned to the VM. If there is not enough XenServer host memory free, then an error will be returned.

The VMs on which this operation should be performed are selected using the standard selection mechanism (see VM selectors for more information).

8.4.23.22. vm-migrate

vm-migrate [[host-uuid=<destination XenServer host UUID> ] | [host=<name or UUID of destination XenServer host> ]] [<vm-selector>=<vm_selector_value>...] [live=<true | false>]

Migrate the specified VMs between physical hosts. The host parameter can be either the name or the UUID of the XenServer host.

By default, the VM will be suspended, migrated, and resumed on the other host. The live parameter activates XenMotion and keeps the VM running while performing the migration, thus minimizing VM downtime to less than a second. In some circumstances such as extremely memory-heavy workloads in the VM, XenMotion automatically falls back into the default mode and suspends the VM for a brief period of time before completing the memory transfer.

8.4.23.23. vm-reboot

vm-reboot [<vm-selector>=<vm_selector_value>...] [force=<true>]

Reboot the specified VMs.

Use the force argument to cause an ungraceful shutdown, akin to pulling the plug on a physical server.

8.4.23.24. vm-reset-powerstate

vm-reset-powerstate [<vm-selector>=<vm_selector_value>...] {force=true}

This is an advanced command only to be used when a member host in a pool goes down. You can use this command to force the pool master to reset the power-state of the VMs to be halted. Essentially this forces the lock on the VM and its disks so it can be subsequently started on another pool host. This call requires the force flag to be specified, and fails if it is not on the command-line.

8.4.23.25. vm-resume

vm-resume [<vm-selector>=<vm_selector_value>...] [force=<true | false>] [on=<XenServer host UUID>]

Resume the specified VMs.

If the VM is on a shared SR in a pool of hosts, use the on argument to specify which host in the pool on which to start it. By default the system will determine an appropriate host, which might be any of the members of the pool.

8.4.23.26. vm-shutdown

vm-shutdown [<vm-selector>=<vm_selector_value>...] [force=<true | false>]

Shut down the specified VM.

Use the force argument to cause an ungraceful shutdown, similar to pulling the plug on a physical server.

8.4.23.27. vm-start

vm-start [<vm-selector>=<vm_selector_value>...] [force=<true | false>] [on=<XenServer host UUID>] [--multiple]

Start the specified VMs.

If the VMs are on a shared SR in a pool of hosts, use the on argument to specify which host in the pool on which to start the VMs. By default the system will determine an appropriate host, which might be any of the members of the pool.

8.4.23.28. vm-suspend

vm-suspend [<vm-selector>=<vm_selector_value>...]

Suspend the specified VM.

8.4.23.29. vm-uninstall

vm-uninstall [<vm-selector>=<vm_selector_value>...] [force=<true | false>]

Uninstall a VM, destroying its disks (those VDIs that are marked RW and connected to this VM only) as well as its metadata record. To simply destroy the VM metadata, use xe vm-destroy.

8.4.23.30. vm-vcpu-hotplug

vm-vcpu-hotplug new-vcpus=<new_vcpu_count> [<vm-selector>=<vm_selector_value>...]

Dynamically adjust the number of VCPUs available to a running paravirtual Linux VM within the number bounded by the parameter VCPUs-max. Windows VMs always run with the number of VCPUs set to VCPUs-max and must be rebooted to change this value.

The paravirtualized Linux VM or VMs on which this operation should be performed are selected using the standard selection mechanism (see VM selectors). Optional arguments can be any number of the VM parameters listed at the beginning of this section.

8.4.23.31. vm-vif-list

vm-vif-list [<vm-selector>=<vm_selector_value>...]

Lists the VIFs from the specified VMs.

The VM or VMs on which this operation should be performed are selected using the standard selection mechanism (see VM selectors). Note that the selectors operate on the VM records when filtering, and not on the VIF values. Optional arguments can be any number of the VM parameters listed at the beginning of this section.

8.4.24. Workload Balancing commands

Commands for controlling the Workload Balancing feature.

8.4.24.1. pool-initialize-wlb

pool-initialize-wlb wlb_url=<wlb_server_address> \
wlb_username=<wlb_server_username> \
wlb_password=<wlb_server_password> \
xenserver_username=<pool_master_username> \
xenserver_password=<pool_master_password>

Starts the workload balancing service on a pool.

8.4.24.2. pool-param-set other-config

Use the pool-param-set other-config command to specify the timeout when communicating with the WLB server. All requests are serialized, and the timeout covers the time from a request being queued to its response being completed. In other words, slow calls cause subsequent ones to be slow. Defaults to 30 seconds if unspecified or unparseable.

xe pool-param-set other-config:wlb_timeout=<0.01> \
uuid=<315688af-5741-cc4d-9046-3b9cea716f69>

8.4.24.3. host-retrieve-wlb-evacuate-recommendations

host-retrieve-wlb-evacuate-recommendations uuid=<vm_uuid>

Returns the evacuation recommendations for a host, and a reference to the UUID of the recommendations object.

8.4.24.4. vm-retrieve-wlb-recommendations

Returns the workload balancing recommendations for the selected VM. The simplest way to select the VM on which the operation is to be performed is by supplying the argument vm=<name_or_uuid>. VMs can also be specified by filtering the full list of VMs on the values of fields. For example, specifying power-state=halted selects all VMs whose power-state is halted. Where multiple VMs are matching, specify the option --multiple to perform the operation. The full list of fields that can be matched can be obtained by the command xe vm-list params=all. If no parameters to select VMs are given, the operation will be performed on all VMs.

8.4.24.5. pool-deconfigure-wlb

Permanently deletes all workload balancing configuration.

8.4.24.6. pool-retrieve-wlb-configuration

Prints all workload balancing configuration to standard out.

8.4.24.7. pool-retrieve-wlb-recommendations

Prints all workload balancing recommendations to standard out.

8.4.24.8. pool-retrieve-wlb-report

Gets a WLB report of the specified type and saves it to the specified file. The available reports are:

pool_health
host_health_history
optimization_performance_history
pool_health_history
vm_movement_history
vm_performance_history

Example usage for each report type is shown below. The utcoffset parameter specifies the number of hours ahead or behind of UTC for your time zone. The start parameter and end parameters specify the number of hours to report about. For example specifying start=-3 and end=0 will cause WLB to report on the last 3 hour's activity.

xe pool-retrieve-wlb-report report=pool_health \
poolid=<51e411f1-62f4-e462-f1ed-97c626703cae> \
utcoffset=<-5> \
start=<-3> \
end=<0> \
filename=</pool_health.txt>

xe pool-retrieve-wlb-report report=host_health_history \
hostid=<e26685cd-1789-4f90-8e47-a4fd0509b4a4> \
utcoffset=<-5> \
start=<-3> \
end=<0> \
filename=</host_health_history.txt>

xe pool-retrieve-wlb-report report=optimization_performance_history \
poolid=<51e411f1-62f4-e462-f1ed-97c626703cae> \
utcoffset=<-5> \
start=<-3> \
end=<0> \
filename=</optimization_performance_history.txt>

xe pool-retrieve-wlb-report report=pool_health_history \
poolid=<51e411f1-62f4-e462-f1ed-97c626703cae> \
utcoffset=<-5> \
start=<-3> \
end=<0> \
<filename=/pool_health_history.txt>

xe pool-retrieve-wlb-report report=vm_movement_history \
poolid=<51e411f1-62f4-e462-f1ed-97c626703cae> \
utcoffset=<-5> \
start=<-5> \
end=<0> \
filename=</vm_movement_history.txt>

xe pool-retrieve-wlb-report report=vm_performance_history \
hostid=<e26685cd-1789-4f90-8e47-a4fd0509b4a4> \
utcoffset=<-5> \
start=<-3> \
end=<0> \
<filename=/vm_performance_history.txt>

Chapter 9. Troubleshooting