Release Notes for Citrix XenServer 6.0 Beta

This document provides important information about the Citrix XenServer 6.0 Beta Release.

Documentation may be updated or changed after the initial release. The Citrix XenServer Beta Central portal contains the latest and most up-to-date information on the Citrix XenServer Beta program. Customers will require a My Citrix account to access this page. If you do not have an account, you can register on the My Citrix home page.

Release notes for Windows and Linux virtual machines (VMs) are available in the Citrix XenServer 6.0 Beta Virtual Machine Installation Guide.

Contents

Licensing

New Features

XenServer Virtual Appliances

Installation and Upgrades

Known Issues and Errata

Documentation and Support

Licensing

Important: Utilizing the XenServer 6.0 Beta advanced features requires a Citrix License Server Virtual Appliance (11.6.1 or higher) and a XenServer 6.0 Beta license. A Citrix License Server Virtual Appliance with a pre-installed XenServer 6.0 Beta license is available for download from the Citrix XenServer Betas & Tech Previews Downloads page. To use an existing Citrix License Server Virtual Appliance, installation of the XenServer 6.0 Beta license is required. For information on downloading and installing the Citrix License Server Virtual Appliance, see the Knowledge Base article Citrix License Server Virtual Appliance for XenServer.

• An overview of licensing in XenServer, including required settings, is in the Citrix XenServer 6.0 Beta Installation Guide.
• For information about obtaining license files and installing a license server, see the Licensing Your Product section on Citrix eDocs.

New Features

We’re pleased to announce availability of the download of XenServer 6.0 Beta. Below is an overview of what’s new in this major XenServer release.

Product Simplification:

• XenServer no longer requires Windows-based virtual machines for features such as StorageLink, Site Recovery, and Workload Balancing. In fact, for StorageLink and Site Recovery, no additional management infrastructure is required at all.
• Workload Balancing (and its Historical Reporting features) have been moved to a Linux-based virtual appliance for easy installation and management.
• The Linux Supplemental Pack has been removed, so there is only 1 base installation ISO. Demo Linux VM functionality has been moved to a virtual appliance format so it can be easily imported onto a host or resource pool. Download the Demo Linux Virtual Appliance from the Citrix XenServer Betas & Tech Previews Downloads page.

Architectural Changes:

• The XenServer 6.0 Beta release is based on the Xen 4.1 hypervisor.
• The Open vSwitch (OVS) is now the default network stack for the product. The OVS was first introduced in XenServer 5.6 Feature Pack 1 as a post-install configuration option and is the basis for the distributed virtual networking (DVS) features, NIC bonding improvements, and jumbo frames support. Improvements to DVS include a "fail-safe" option and various improvements based on customer feedback from XenServer 5.6 Feature Pack 1. Note that the legacy Linux bridging stack is still available via a post-install configuration option.
• General network performance has been improved, particularly aggregate host network throughput; internal measures vs. prior XenServer releases show gains of 70-100% in some instances.
• Support for hardware-assisted (SR-IOV) network performance optimizations has been improved, particularly for use with the NetScaler VPX and SDX products.

Tools for Self-Service and Building Clouds:

• The new Self-Service Manager feature enables you to build self-service environments for private clouds. Self-Service Manager includes support for both XenServer as well as VMware vSphere.
• Self-Service Manager is easy to deploy and manage via a simple virtual appliance and web-based UI. It offers multi-tenant support for creating VM "service catalogs" used by delegated administrators to deploy and manage their own applications and resources.
• Virtual Appliance support. Within XenCenter you can create multi-VM virtual appliances, with relationships between the VMs for use with HA and Site Recovery such as boot sequence. Virtual appliances can be easily imported and exported using the Open Virtualization Format (OVF) standard.
• VMDK and VHD import functionality is integrated into XenCenter for interoperability with VMware VMDK and Microsoft VHD disk images.

Microsoft System Center Integration:

• Starting with the XenServer 6.0 Beta release, you will have the option of managing XenServer hosts and VMs with Microsoft System Center Virtual Machine Manager (VMM) 2012. For more information refer to the Microsoft System Center 2012 beta page.
• System Center Operations Manager 2012 will be able to manage and monitor XenServer hosts and virtual machines.
• System Center integration is available with a special supplemental pack from Citrix, which is targeted for general availability when System Center 2012 ships later this year.

XenDesktop:

• 6.0 Beta is the first XenServer release to include HDX enhancements for optimized user experience with virtual desktops.
• With the 6.0 Beta release, a physical GPU can be assigned to a VM so the applications running in the guest can leverage GPU instructions ("GPU Pass-Through"). This provides significant TCO benefits for the XenDesktop HDX 3D Pro technology used for delivery of CAD and other graphical applications via virtual desktops. With GPU pass-thru, either a single GPU card or a GPU on a multi-GPU card can be assigned to virtual machines.

Guest OS Support Updates

• Formal guest support for Ubuntu 10.04.
• Updates for support of RHEL 5.6, CentOS 5.6, and SLES 10 SP4.
• Experimental VM templates for Solaris and Ubuntu 10.10.
• RHEL 6.0 and Debian Squeeze are now fully supported (support introduced in XenServer 5.6 Service Pack 2).

Other Enhancements and Improvements:

• A Rolling Pool Upgrade wizard is provided in XenCenter to enable more reliable upgrades from 5.6, 5.6 Feature Pack 1 and 5.6 Service Pack 2.
• High Availability (HA) now supports NFS for storage of the heartbeat disk.
• Host RAM support has been increased to 1 TB.
• VM vCPU and vRAM support has been increased: up to 16 vCPUs and 128 GB RAM for Windows; increased Linux vCPU and vRAM support levels vary by distro.
• NIC bonding reliability is improved, and formal support for active/passive bonding has been added.
• XenCenter will be localized into Japanese and Simplified Chinese (these will be generally available a few months following the English release).

Noteworthy Changes to Existing Features:

• Lab Manager has been superseded by Self Service Manager. Lab Manager will continue to be supported with XenServer 5.x until September 2013 according to the lifecycle policy.
• With the move from the Windows-based StorageLink Gateway to integrated StorageLink, some StorageLink array support is being retired. Focus for integrated StorageLink support is being placed on arrays with standards-based SMI-S interfaces (e.g. EMC CLARiiON) and those which are widely used with XenServer (NetApp and Dell EqualLogic). Arrays whose StorageLink supportability is being retired will continue to be supported via the standard iSCSI and Hardware HBA Storage Repository types. StorageLink Gateway will continue to be supported with XenServer 5.x until September 2013 according to the lifecycle policy. Note also that the new rolling pool upgrade takes care of upgrading from StorageLink Gateway and checking for the presence of any unsupported arrays.
• Site Recovery: Site Recovery is no longer based on StorageLink. Disaster Recovery is now supported for virtually any iSCSI or FC based array which has replication features, as well as third-party replication scenarios.

XenServer Virtual Appliances

The following XenServer virtual appliances are available for download from the Citrix XenServer Betas & Tech Previews Downloads page:

• Demo Linux Virtual Appliance
• Workload Balancing Virtual Appliance
• Citrix License Server Virtual Appliance
• vSwitch Controller Virtual Appliance

Installation and Upgrades

Upgrade to XenServer 6.0 Beta is possible from any version of XenServer 5.6 including 5.6 (base), 5.6 Feature Pack 1, and 5.6 Service Pack 2. It is also possible to upgrade from XenServer Project Boston Beta.

Upgrading XenServer

Fresh Installation of XenServer 6.0 Beta

Known Issues and Errata

This section details known issues with this release and any workarounds that can be applied.

General

• Migrating or saving and restoring Windows VMs within heterogeneous pools may fail. [CA-60314]
• If all hosts in an HA-protected pool are powered off, and one slave is rebooted without access to the HA heartbeat storage repository, then the slave will not be manageable. To resolve this, power on the master host. [CA-49870]
• A Windows VM may fail to boot properly if streaming over Citrix Provisioning Services (PVS). This is an intermittent fault, and rebooting the VM should resolve the issue. [CA-60261]
• If a VM is assigned to a multi-function graphics card (for example, a card with separate video and audio functions), the card may appear to be disabled and GPU Pass-Through may not work properly. This issue may be resolved by rebooting the host. [CA-61864]
• Attempting to revert back to a snapshot with memory, which has the XenServer Tools ISO in the DVD drive on a host that has been upgraded from an older version of XenServer, will produce a VM that cannot be restarted properly. You can start the suspended VM by forcibly shutting it down and emptying the DVD drive; however, the memory portion of the snapshot will be lost. [CA-59289]
• Due to the way in which the Broadcom bnx2x driver allocates memory, the /etc/modprobe.d/bnx2x file sets num_queues=1 and disables transparent packet aggregation for Broadcom 10 Gb/s Ethernet NICs. This ensures that Dom0 has enough available memory for normal operation, but may result in performance degradation when these NICs are used. Increasing the value of num_queues up to 4 may help in this regard. [CA-60549]
• If upgrading from XenServer Project Boston Beta to XenServer 6.0 Beta, do not uninstall the older XenServer Tools before installing the new Tools. If the older XenServer Tools are uninstalled first, the installation of the new Tools will fail. If the installation fails for this reason, a second attempt at installing the new Tools will succeed. [CA-62082]

Internationalization

• Non-ASCII characters, such as characters with accents, cannot be used in the host console. [CA-40845]
• The root password of the host installer must not contain non-ASCII characters. [CA-47461]
• The password for CIFS storage repositories must not contain non-ASCII characters. [CA-29017]

Hardware Compatibility

• If you are running XenServer Project Boston Beta on HP Generation 6 hardware with SmartArray storage controllers, upgrading to XenServer 6.0 Beta will fail. Upgrading from XenServer versions 5.6, 5.6 Feature Pack 1 and 5.6 Service Pack 2 will succeed. [CA-58379]

Networking

• If you attempt to set up an active/passive bond between two NICs, occasionally the bond may be created as active/active. If this occurs, reboot the host and the bond will come up correctly as active/passive. [CA-62068]
• DHCP lease renewal fails if the DHCP client and DHCP server are both Linux VMs on the same host. This does not affect Windows VMs. If you want to use dhcp3-server and dhcp3-client in Linux VMs which may be sharing the same host, you must disable checksum offload by issuing the command ethtool -K eth0 tx off on the DHCP server VM. [CA-40908]

Storage

• If your resource pool has an existing connection to a CIFS ISO share, subsequent attempts to create a new ISO SR on that same share may fail. [CA-37251]
• Quiesced snapshots are not supported for Windows Server 2008 R2 VMs. [CA-32734]
• If you attempt to include a shared storage device in the list of devices to be incorporated into a host's local SR (in an answerfile that is used to automate XenServer installation), the contents of the shared storage will be destroyed. [CA-41786]
• Writing to CIFS ISO storage repositories is not supported and can result in disk corruption. [CA-41058]
• If your ISO SR is on an NFS server and the connection to the server is temporarily lost, you may need to restart your XenServer host in order to regain connection. [CA-10471]
• Live migration is not supported for VMs that have at least one disk hosted on a shared StorageLink SR using the NetApp adapter. If attempted, this might lead to I/O corruption, and you will need to take the following steps to rectify the VM state:
  1. Force shut down the VM.
  2. Detach the respective SR from the pool.
  3. Re-attach the SR on the pool.
  4. Start the VM.
  Important: Due to this issue, rolling pool upgrades will not function as expected if the pool is hosting any VMs with storage on a shared StorageLink SR using the NetApp adapter. [CA-61934]

XenCenter

• Modifying the font size or DPI on the computer on which XenCenter is running can result in the user interface displaying incorrectly. The default font size is 96 DPI; Windows Vista refers to this as "Default Scale" and Windows 7 as "100%". [CA-45514]
• Importing an .ova or .ova.gz file from a directory for which the user has read-only access will fail. Write permission is required to uncompress the .ova.gz file and extract the .ovf package files from the .ova file. [CA-61238]
• The Disaster Recovery wizard occasionally shows neither vApps nor VMs on the Select vApps & VMs page. If this issue occurs, wait 30 seconds, click Previous and then Next on the wizard. The vApps and VMs should then appear. [CA-61929]
• Before using the Rolling Pool Upgrade wizard, you must add XenServer 6.0 Beta licenses to your license server. Failure to do so will result in your XenServer hosts being unlicensed after the upgrade, and VMs unable to start or resume. [CA-62036]

Guest OS Support

• The Ubuntu 10.04 i386 kernel in the apt-repository at time of writing does not boot in 32-bit VMs with more than 512MB. This bug was introduced between linux-image-2.6.32-30-generic-pae-2.6.32-30.59 and linux-image-2.6.32-32-generic-pae-2.6.32-32.62. For more information, see Ubuntu Launchpad 803811 and 790747. [CA-61400]
• Significant CPU time can be taken by the Debian Squeeze Graphical Desktop Environment, which uses the Gnome Display Manager daemon. Citrix strongly advises that customers do not install the Gnome Display Manager gdm3 process, or uninstall it if already installed. [CA-48630]
• A guest operating system which does not support Dynamic Memory Control (DMC) will not display an error message if you attempt to configure DMC on the guest. [CA-34753]
• When running greater than 50 VMs per XenServer host, the steps in CTX126531 should be followed to reconfigure Dom0 memory settings. [CA-48485]
• The XenServer Tools in Windows VMs imported from XenServer 4.0 are not compatible with this release. If the XenServer Tools are allowed to start, then this may cause filesystem corruption. If the imported VM has the Tools installed, first boot the VM in safe mode (by hitting F8) and uninstall the old Tools before rebooting normally and installing the new Tools. [CA-32958]
• The RHEL 6.0 kernel has a bug which affects disk I/O on multiple virtualization platforms. This issue causes VMs running RHEL 6.0 to lose interrupts. For more information, see Red Hat Bugzilla 681439, 603938 and 652262. [CA-60495]

Documentation and Support

Finding Documentation

For the most up-to-date product documentation for every Citrix product, visit the Citrix Product Documentation links page or, for many products, Citrix eDocs.

For licensing documentation, go to the Licensing Your Product section on Citrix eDocs.

Getting Support

Citrix provides technical support primarily through Citrix Solutions Advisors. Contact your supplier for first-line support, or use Citrix Online Technical Support to find the nearest Citrix Solutions Advisor.

Citrix offers online technical support services on the Citrix Support Web Site. This site includes links to downloads, the Citrix Knowledge Center, Citrix Consulting Services, and other useful resources.

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