Release Notes for Citrix XenServer 6.0Documentation may be updated or changed after the initial release. Citrix suggests regularly visitingthe XenServer 6.0 page on the Citrix Support Website to learn about updates.Release notes for Windows and Linux virtual machines (VMs) are available in the Citrix XenServer 6.0Virtual Machine Installation Guide/ContentsLicensingNew FeaturesXenServer Virtual AppliancesInstallation and UpgradesKnown Issues and ErrataDocumentation and SupportLicensingImportant: Utilizing the XenServer 6.0 advanced features requires a Citrix License Server Virtual Appliance(11.6.1 or higher) and a XenServer 6.0 license. A Citrix License Server Virtual Appliance with a pre-installedXenServer 6.0 license is available for download from the Citrix XenServer 6.0 Download page. To use anexisting Citrix License Server Virtual Appliance, installation of the XenServer 6.0 license is required. Forinformation on downloading and installing the Citrix License Server Virtual Appliance, see the KnowledgeBase article CTX124501-Citrix License Server Virtual Appliance for XenServer. An overview of licensing in XenServer, including required settings, is in the Citrix XenServer 6.0Installation Guide.For information about obtaining license files and installing a license server, see the Licensing YourProduct section on Citrix Product Documentation.New FeaturesWe're pleased to announce availability of the download of XenServer 6.0. XenServer 6.0 includes a numberof new features and ongoing improvements, including:Integrated Site Recovery (Disaster Recovery). Remote data replication between storage arrays with fastrecovery and failback capabilities. Integrated Site Recovery replaces StorageLink Gateway Site Recoveryused in previous versions, removes the Windows VM requirement, and works with any iSCSI or HardwareHBA storage repository.Integrated StorageLink. Access to use existing storage array-based features such as data replication, deduplication, snapshot and cloning. Replaces the StorageLink Gateway technology used in previous editionsand removes requirement to run a Windows VM with the StorageLink components.

GPU Pass-Through. Enables a physical GPU to be assigned to a VM providing high-end graphics. Allowsapplications to leverage GPU instructions in XenDesktop VDI deployments with HDX 3D Pro.Virtual Appliance Support (vApp). Ability to create multi-VM and boot sequenced virtual appliances(vApps) that integrate with Integrated Site Recovery and High Availability. vApps can be easily imported andexported using the Open Virtualization Format (OVF) standard.Rolling Pool Upgrade Wizard. Simplify upgrades (automated or semi-automated) to XenServer 6.0 with awizard that performs pre-checks with a step-by-step process that blocks unsupported upgrades.Microsoft SCVMM & SCOM Support. Manage XenServer hosts and VMs with System Center VirtualMachine Manager (SCVMM) 2012. System Center Operations Manager (SCOM) 2007 R2 will also be ableto manage and monitor XenServer hosts and VMs. System Center integration is available with a specialsupplemental pack from Citrix. For more information refer to the Microsoft System Center 2012 VirtualMachine Manager page.Distributed Virtual Switch Improvements. New fail safe mode allows Cross-Server Private Networks,ACLs, QoS, RSPAN and NetFlow settings to continue to be applied to a running VM in the event of vSwitchController failure.Increased Performance and Scale. Supported limits have been increased to 1 TB memory for XenServerhosts, and up to16 virtual processors and 128 GB virtual memory for VMs. Improved XenServer Tools withsmaller footprint.Networking Improvements. Open vSwitch is now the default networking stack in XenServer 6.0 and nowprovides formal support for Active-Backup NIC bonding.VM Import & Export Improvements. Full support for VM disk and OVF appliance imports directly fromXenCenter with the ability to change VM parameters (virtual processor, virtual memory, virtual interfaces,and target storage repository) with the Import wizard. Full OVF import support for XenServer, XenConvertand VMware.SR-IOV Improvements. Improved scalability and certification with the SR-IOV Test Kit. Experimental SRIOV with XenMotion support with Solarflare SR-IOV adapters.Simplified Installer. Host installations only require a single ISO.Enhanced Guest OS Support. Support for Ubuntu 10.04 (32/64-bit). Updated support for Debian Squeeze6.0 64-bit, Oracle Enterprise Linux 6.0 (32/64-bit) and SLES 10 SP4 (32/64-bit). Experimental VM templatesfor CentOS 6.0 (32/64-bit), Ubuntu 10.10 (32/64-bit) and Solaris 10.Workload Balancing Improvements. New, ready-to-use Linux-based virtual appliance with a smallerfootprint replaces the Windows-based virtual appliance and eliminates the Windows licensing dependency.XenDesktop Enhancements. HDX enhancements for optimized user experience with virtual desktops,GPU Pass-Through, and increased VM and XenServer host limits.VM Protection & Recovery. Now available for Advanced, Enterprise and Platinum Edition customers.NFS Support for High Availability. HA Heartbeat disk can now reside on a NFS storage repository.XenCenter Improvements. XenCenter operations now run in parallel, and XenCenter will be available inJapanese and Simplified Chinese (ETA Q4 2011).Host Architectural Improvements. XenServer 6.0 now runs on the Xen 4.1 hypervisor, provides GPTsupport and a smaller, more scalable Dom0.

XenServer Virtual AppliancesThe following XenServer virtual appliances are available for download from the Citrix XenServer 6.0Download page: Demo Linux Virtual ApplianceWorkload Balancing Virtual ApplianceCitrix License Server Virtual AppliancevSwitch Controller Virtual ApplianceInstallation and UpgradesUpgrade to XenServer 6.0 is possible from any version of XenServer 5.6 including 5.6 (base), 5.6 FeaturePack 1, and 5.6 Service Pack 2.Upgrading XenServerCustomers upgrading from XenServer 5.6 and later should follow the instructions below. These instructionsapply to customers using the XenCenter Rolling Pool Upgrade wizard to upgrade XenServer hosts or pools.For details on upgrading XenServer using the xe CLI, please refer to the XenServer 6.0 Installation Guide.Note: For information on upgrading the vSwitch Controller Virtual Appliance, see the XenServer 6.0 vSwitchController User Guide.Before You Upgrade Download the 6.0 version of XenCenter.Citrix strongly recommends that you take a backup of the state of your existing pool using the pooldump-database xe CLI command (see the XenServer 6.0 Administrator's Guide).Consider suspending any non-critical VMs to ensure that hosts have sufficient memory to carry outthe upgrade.To Upgrade XenServer Using the XenCenter Rolling Pool UpgradeWizard: the Rolling Pool Upgrade wizard: on the Tools menu, select Rolling Pool Upgrade.Read the Before You Start information, and then click Next to continue.Select the pool(s) and/or individual hosts that you wish to upgrade, and then click Next.Choose Automatic Mode or Manual Mode, depending on whether you are planning an automatedupgrade from network installation files located on an HTTP, NFS or FTP server, or a manualupgrade from either a CD/DVD or via PXE boot (using already existing infrastructure).Note: If you choose Manual Mode, you must run the XenServer installer on each XenServer hostin turn and follow the on-screen instructions on the serial console of the host. Once the upgradebegins, XenCenter prompts you to insert the XenServer installation media or to specify a PXE bootserver for each host that you upgrade.5.6.Once you have selected your Upgrade Mode, click Run Prechecks.Follow the recommendations to resolve any upgrade prechecks that have failed. If you would likeXenCenter to attempt to automatically resolve all failed prechecks, click Resolve All.Once all prechecks have been resolved, click Next to continue.7.Prepare the XenServer installation media.

oIf you chose Automatic Mode, enter the installation media details.Choose HTTP, NFS or FTP and then specify the path, username and password, asappropriate.Note: Enter the username and password associated with your HTTP, NFS or FTP server,if you have configured security credentials for this server. Do not enter the username andpassword associated with your XenServer pool.oIf you chose Manual Mode, note the upgrade plan and instructions.Click Start Upgrade.8.Once the upgrade begins, the Rolling Pool Upgrade wizard guides you through any actions youneed to take to upgrade each host. Follow the instructions until you have upgraded all hosts in thepool(s).Once the upgrade completes, the wizard prints a summary. Click Finish to close the wizard.Fresh Installation of XenServer 6.0To perform a fresh installation of XenServer 6.0, please refer to the instructions in the XenServer 6.0Installation Guide.Known Issues and ErrataThis section details known issues with this release and any workarounds that can be applied.General Citrix strongly recommends using the new XenServer 6.0 Disaster Recovery feature, as the legacyMetadata Backup, Restore and Update mechanism (accessible via the XenServer host console)will be deprecated in a future XenServer release. Citrix advises customers using the legacymechanism to migrate to the new, integrated feature. [CA-65906]In some 10 Gigabit Ethernet environments, occasional performance problems with disk throughputon NFS SRs have been observed. The problem can be identified by a log entryin /var/log/messages similar to: kernel: nfs: server notresponding, timed out. Citrix continues to investigate this issue with an aim to resolve it ina future release. [CA-59187]If your XenServer hosts are configured with static IP addresses, be sure that the switch portsconnected to the XenServer hosts are configured as detailed in the Knowledge Basearticle CTX123158-Considerations for Connecting XenServer to the Switch Ports before attemptingan upgrade. [CA-66492]A Windows VM may fail to boot properly if streaming over Citrix Provisioning Services (PVS). Thisis an intermittent fault, and rebooting the VM should resolve the issue. [CA-60261]Attempting to revert back to a snapshot with memory, which has the XenServer Tools ISO in theDVD drive on a host that has been upgraded from an older version of XenServer, will produce aVM that cannot be restarted properly. You can start the suspended VM by forcibly shutting it downand emptying the DVD drive; however, the memory portion of the snapshot will be lost. [CA-59289]If upgrading from Beta versions of XenServer 6.0 (XenServer Project Boston Beta and XenServer6.0 Beta) to XenServer 6.0, do not uninstall the older XenServer Tools before installing the newTools. If the older XenServer Tools are uninstalled first, the installation of the new Tools will fail. Ifthe installation fails for this reason, a second attempt at installing the new Tools will succeed. [CA62082]

If a VM is protected by a VM Protection Policy, and then that VM is converted to a template, the VMProtection Policy will fail to run in the future. To avoid this issue, you should first remove the VMfrom the VM Protection Policy before converting it to a template. [CA-62503]XenServer reports the amount of space used by a virtual disk, but this number can be substantiallyout of date. [CA-51466]Internationalization Non-ASCII characters, such as characters with accents, cannot be used in the host console. [CA40845]The root password of the host installer must not contain non-ASCII characters. [CA-47461]The network path and login credentials (username/password) for CIFS storage repositories mustnot contain non-ASCII characters. [CA-29017] [CA-64182]LocalizationFor XenServer 6.0, XenCenter is available in Japanese and Simplified Chinese. Documentation forXenServer 6.0 is available in Japanese, Simplified Chinese, Traditional Chinese, and Korean. TheJapanese/Simplified Chinese version of XenCenter detects the user's system locale and the operatingsystem language to choose the language of the XenCenter graphical user interface.Hardware Compatibility Intel Errata for Nehalem and Westmere CPU implementations of C-states may lead to systeminstability, apparently random freezes or reboots — including during installation. Customers withNehalem and Westmere CPUs are advised to disable C-states in the system BIOS as detailed inthe Knowledge Base article CTX127395-Hosts Become Unresponsive with XenServer on Nehalemand Westmere CPUs. [CA-60628]Networking DHCP lease renewal fails if the DHCP client and DHCP server are both Linux VMs on the samehost. This does not affect Windows VMs. If you wish to use dhcp3-server and dhcp3-client in LinuxVMs which may be sharing the same host, you must disable checksum offload by issuing thecommand ethtool -K eth0 tx off within the DHCP server VM. [CA-40908]After migration, Windows-based VMs may see a drop in network throughput to other VMs on thesame host. Traffic from VMs to machines on different hosts is unaffected. To work around thisissue: after migration, open theDevice Manager on the VM and select the PV network interface.Right-click the PV network interface and select Properties. In the dialog box, selectthe Advanced tab, and then select Large Receive Offload (IPv4). Change the value to Disabled,and then click OK. If you then repeat this procedure but set the value back to Enabled, it should reactivate LRO and rectify the performance problem. [CA-65342]If you are using Internet Explorer (IE) version 7 or 8 to access the vSwitch Controller interfaceremotely, you may find that these versions of IE leak system handles. Citrix recommends usingeither Firefox or IE 9, which addresses some of the known IE memory and resource leak issues. Tohelp prevent leak issues, the vSwitch Controller GUI now logs out a user after approximately 10hours if the user has not manually refreshed or navigated away from a webpage. The logout willreclaim memory used by the browser. [CA-65261]When NIC bonds are deleted, the vSwitch Controller GUI may fail to show the slave networks thathad been bonded. To resolve this issue, refresh the status of the pool or restart the vSwitchController. The networks should then reappear. [CA-65261]If RSPAN is configured, and you add a pool or network to your vSwitch Controller at the AllResource Pools level, then RSPAN will not work properly on the newly-added pool or network.Even though an RSPAN policy appears to be set using the configured RSPAN Target VLAN ID, noRSPAN traffic is detected. To work around this issue, the vSwitch Controller administrator can addadditional RSPAN Target VLAN IDs after adding the new pool or network. This will refresh the

target VLAN IDs for all pools. The additional IDs can then be removed if they are not needed. [CA65261]Storage If your resource pool has an existing connection to a CIFS ISO share, subsequent attempts tocreate 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 an SR has very little free space, a reversion to a snapshot may fail. This issue can be resolved byre-attempting the revert a few minutes later. [CA-63032]If you attempt to include a shared storage device in the list of devices to be incorporated into ahost's local SR (in an answerfile that is used to automate XenServer installation), the contents ofthe shared storage will be destroyed. [CA-41786]Writing to CIFS ISO storage repositories is not supported and can result in disk corruption. [CA41058]If your ISO SR is on an NFS server and the connection to the server is temporarily lost, you mayneed to restart your XenServer host in order to regain connection. [CA-10471]XenCenter If you attempt to edit the networks of a VM using XenCenter, and the operation fails,the Networking tab may become blank for all your servers and VMs. The problem can be resolvedby closing and reopening XenCenter. [CA-66815]If you are using the XenCenter Rolling Pool Upgrade wizard to upgrade an HA-enabled pool, thewizard may display the status message The value '1' is invalid for field'ha restart priority' for the task 'Revert precheck actions' on the Apply Upgrade pageof the wizard. If this happens, you will need to manually re-enable HA on the upgraded pool inorder for the pool to be HA-protected. [CA-66495]Modifying the font size or DPI on the computer on which XenCenter is running can result in theuser 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 fromthe .ova file. [CA-61238]Guest OS Support If you wish to create an Ubuntu 10.04 VM (32-bit) with more than 512MB of memory, you mustrun sudo apt get upgrade to upgrade to the latest version of the kernel before increasingthe RAM to greater than 512MB. Upgrading to the latest version of the kernel is necessary due to abug that was introduced between linux-image-2.6.32-30-generic-pae-2.6.32-30.59 and linux-image2.6.32-32-generic-pae-2.6.32-32.62. It was fixed in linux-image-2.6.32-33-generic-pae-2.6.3233.64. For more information, see Ubuntu Launchpad 803811 and 790747. [CA-61400]Ubuntu 10.04 (64-bit) running the 2.6.32-32 #72 kernel, has been known to crash with the followingmessage, kernel BUG at 343!. The problem only affects VMs with multiplevCPUs. vCPU hotplugging (only available via the xe CLI/API) should not be attempted with thisguest. [CA-57168]Significant CPU time can be taken by the Debian Squeeze Graphical Desktop Environment, whichuses the Gnome Display Manager daemon. Citrix strongly advises that customers do not install theGnome Display Managergdm3 process, or uninstall it if already installed. [CA-48630]A guest operating system which does not support Dynamic Memory Control (DMC) will not displayan error message if you attempt to configure DMC on the guest. [CA-34753]Using DMC with RHEL or CentOS 5.3 or 5.4 (32-/64-bit) may cause the guest to crash. If you wishto use DMC, Citrix strongly recommends using a later version of RHEL or CentOS. [EXT-54]

When running greater than 50 VMs per XenServer host, the steps in CTX126531-How to Configuredom0 Memory in XenServer 5.6 and 6.0.x should be followed to reconfigure Dom0 memorysettings. [CA-48485]The XenServer Tools in Windows VMs imported from XenServer 4.0 are not compatible with thisrelease. If the XenServer Tools are allowed to start, then this may cause filesystem corruption. Ifthe imported VM has the Tools installed, first boot the VM in safe mode (by hitting F8) and uninstallthe 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. Thisissue causes VMs running RHEL 6.0 to lose interrupts. For more information, see Red HatBugzilla 681439, 603938 and 652262. [CA-60495]Documentation and SupportFinding DocumentationFor the most up-to-date product documentation for every Citrix product, visit Citrix Product Documentation.For licensing documentation, go to the Licensing Your Product section on Citrix Product Documentation.Getting SupportCitrix provides technical support primarily through Citrix Solutions Advisors. Contact your supplier for firstline 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 todownloads, the Citrix Knowledge Center, Citrix Consulting Services, and other useful resources.Copyright 2012 Citrix Systems, Inc. All rights reserved.Citrix and Xen are registered trademarks. XenServer and XenCenter are trademarks of CitrixSystems, Inc. in the United States and other countries.All other trademarks and registered trademarks are the property of their respective owners.

Release Notes for Citrix XenServer 6.0 Documentation may be updated or changed after the initial release. Citrix suggests regularly visiting the XenServer 6.0 page on the Citrix Support Website to learn about updates. Release notes for Windows and Linux virtual machines (VMs) a