XenServer Release Notes

Release 4.0.1, Build 4442x

Xen®, XenSource™, XenEnterprise™, XenServer™, XenExpress™, XenCenter™ and logos are either registered trademarks or trademarks of XenSource, Inc. in the United States and/or other countries. Other company or product names are for informational purposes only and may be trademarks of their respective owners.

This product contains an embodiment of the following patent pending intellectual property of XenSource, Inc.:

United States Non-Provisional Utility Patent Application Serial Number 11/487,945, filed on July 17, 2006, and entitled “Using Writeable Page Tables for Memory Address Translation in a Hypervisor Environment”.
United States Non-Provisional Utility Patent Application Serial Number 11/879,338, filed on July 17, 2007, and entitled “Tracking Current Time on Multiprocessor Hosts and Virtual Machines”.

October 2007

Table of Contents

1. About this Document
2. Installation
3. New In This Release
4. Known Issues

1. About this Document

This document lists known issues in the current release of XenServer™. Where possible, workarounds are described.

Release Notes specific to the supported Windows Virtual Machines are present in the "Installing Windows VMs" chapter of the XenServer Virtual Machines Installation Guide. Release Notes specific to the supported Linux Virtual Machines are present in the "Installing Windows VMs" chapter of the same document.

For the latest up-to-date version of the XenServer release notes, visit the XenServer v4 Documentation page.

For further product usage information, or to find how you should report problems, visit the XenSource Support page.

2. Installation

System requirements, preparation, installation, and initial configuration are described in the Getting Started With XenServer document.

3. New In This Release

This release of the XenServer product family contains the following new features:

The Xen hypervisor runs in 64-bit mode, and supports up to 128GB of host memory. All Windows VMs also support up to 32GB of memory per VM, and have improved network performance. The control domain is based on a 32-bit EL5-based distribution.
VMs running unmodified Windows Server 2003 SP2 in 64-bit mode are supported (on computers with hardware virtualization support - Intel VT or AMD-V CPUs)
VMs running unmodified Windows 2000 support multiple virtual CPUs and use the ACPI APIC Hardware Abstraction Layer (HAL).
Red Hat Enterprise Linux 5 and SUSE Enterprise Linux 10 may be installed directly from vendor network repositories using the vendor-provided Xen kernels, and thus no longer require hardware-assisted virtualization during the installation process.
XenServer hosts with homogenous hardware can now be combined into pools of up to 16 hosts, with shared storage and live relocation of Linux and Windows VMs using XenMotion™.
Windows VM support hot-plugging of disks and network interfaces while they are running, subject to support from the operating system.
The Xen Application Programming Interface is available on the XenServer host. XenCenter is a native Windows interface which provides an easy-to-use graphical interface, and a complete Command-Line Interface (with tab-completion on Linux hosts) is also provided.
An extensible storage manager which supports a block-backed volume manager, a file-backed VHD-based backend, and iSCSI-based volumes. These can operate as local repositories or as shared storage as part of a pool.

4. Known Issues

CA-333: When booting the XenServer Host after installation, the message “Loading GRUB, please wait” is displayed, followed by several “Press any key to continue” messages. This allows you to press a key on either the physical console or a serial console and let GRUB know where to direct its output. If you wait, the GRUB menu is automatically directed to the physical console.Note that on some machines, the BIOS causes the pause between these messages to be unusually long, such that it takes over a minute for it to automatically direct to the physical console.

CA-933: On machines with multiple disks, the XenServer boot loader is only written to the disk selected for installation.For example, if you set the boot drive to the first disk, and then install XenServer Host on the second drive, and then subsequently change the system BIOS to assign the second drive to be the boot drive, it will fail to boot and properly renumber the disks. Installation to the second disk only works if the first disk has a boot loader already present which lets you boot off second disk, or if the BIOS permits you to boot directly off the second disk. Renumbering disks post-installation will not work. The only workaround is to manually edit menu.lst .

CA-4065: When installing a Windows VM, if you leave the installer sitting at the first couple of prompt screens, the CPU usage on the XenServer Host (and on the VM) spikes to 100%. While this is going on, performance of other guests on the system may be reduced.As soon as you press a key to respond to these prompts, everything behaves normally again. This only occurs during the early part of Windows installation and does not affect normal operation.

CA-4575, CA-5311: On servers with the ICH8 South Bridge chipset, XenServer might not detect the drive at installation due to a problem with the ata_piix driver. If you have this problem, set the machine's ATA/IDE mode in the Advanced section of the BIOS to use the Advanced Host Controller Interface (AHCI). This is usually set to off (legacy mode) by default. You might need to set the mode to "Native" to then access further SATA configuration options that allow selecting between AHCI, IDE, or RAID. It might also be available via Advanced->Drive Configuration->Disable Intel® RAID Technology and then Enable SATA AHCI mode The Dell SAS 5/iR Controller in Dell 490 hosts exhibits this issue.For more information, see http://www.intel.com/support/chipsets/imst/sb/cs-015988.htm.

CA-5785: The Acronis Rescue CD does not work in a VM. It uses CPU features that Xen does not yet support.

CA-7360: If a VM has an NFS Storage Repository, and the NFS service is somehow terminated, the Storage Repository still appears to be active from the XenCenter New VM wizard. If you attempt to create a new VM on this SR, the VM will appear to be stuck in the "creating" state.

CA-8767: Motherboards using the Intel 965 chipset with more than 2GB of memory may fail to boot successfully. This has been identified as a BIOS firmware issue, and appears to happen on any 64-bit operating systems (see Red Hat and Microsoft related bugs). To workaround this, downgrade your BIOS to version 1669, available from the Intel website.

CA-9345: Setting virtual disk QoS via XenCenter does not work. You must use the xe CLI commands if you want to change this. Refer to the section "Virtual disk QoS settings" in the XenServer Administrator's Guide. This effects XenEnterprise customers only.

CA-9208: XenSource has seen data corruption issues using the iSCSI target provided by Adaptec SnapServers. This appears to be a problem with the SnapServer iSCSI implementation, and has been reproduced by Adaptec using a standard (non-XenServer) Linux distribution. We are currently working with Adaptec to find a solution to this problem. Until this issue is resolved, XenServer users are strongly encouraged to use NFS rather than iSCSI storage repositories when using SnapServer products.