Known issues

This article contains advisories and minor issues in Citrix Hypervisor 8.0 release and any workarounds that you can apply.

General

  • A pool’s CPU feature set can change while a VM is running. (For example, when a new host is added to an existing pool, or when the VM is migrated to a host in another pool.) When a pool’s CPU feature set changes, the VM continues to use the feature set which was applied when it was started. To update the VM to use the pool’s new feature set, you must power off and then start the VM. Rebooting the VM, for example, by clicking ‘Reboot’ in XenCenter, does not update the VM's feature set. (CA-188042)

  • The increase in the amount memory allocated to dom0 in Citrix Hypervisor 8.0 can mean there is slightly less memory available for running VMs. On some hardware, you might not be able to run the same number of VMs with Citrix Hypervisor 8.0 as you could on the same hardware with a previous version of XenServer. (CP-29627)

  • When attempting to use the serial console to connect to a Citrix Hypervisor server, the serial console might refuse to accept keyboard input. If you wait until after the console refreshes twice, the console then accepts keyboard input. (CA-311613)

  • When using a clustered pool, if you use the same network for clustering as you do for management or storage, moderate load can cause the whole cluster to self-fence. (CA-312476)

Graphics

  • If you forcibly shut down a VM that has an AMD MxGPU attached, or the guest OS shuts down abnormally, your Citrix Hypervisor server might experience memory corruption. Perform a co-operative shutdown to ensure the hardware is correctly cleaned up during the shutdown process. (CA-297891)

  • When you start in parallel many VMs with AMD MxGPU devices attached, some VMs might fail with a VIDEO_TDR_FAILURE. This might be due to a hardware limitation. (CA-305555)

  • On rare occasions, VMs with attached NVIDIA vGPUs can become stuck in a yellow state at VM start. This is likely to be caused by one of the vGPUs having “compatibility-metadata” set when it should not. To remove the metadata, suspend and resume the VM. (CA-312226)

Guests

  • On Citrix Hypervisor hosts that use the bnxt_en driver, Oracle 6.x VMs can crash when connecting to a network. Ensure that your bnxt_en driver is up-to-date by installing the following driver disk: Driver Disk for Broadcom bnxt_en-1.8.29 - For XenServer 7.x CR. (CA-288010)

  • On rare occasions, suspending or migrating a Linux VM with outstanding xenstore transactions can hang due to an issue in the VM’s Linux kernel. If your VM experiences this issue, force the VM to shut down and restart it. (CP-30551)

Internationalization

  • Non-ASCII characters, for example, characters with accents, cannot be used in the host console. (CA-40845)

  • In a Windows VM with Citrix VM Tools installed, copy and paste of double-byte characters can fail if using the default desktop console in XenCenter. The pasted characters appear as question marks (?). To work around this issue, you can use the remote desktop console instead. (CA-281807)

Storage

  • If you use GFS2 SRs and have two servers in your clustered pool, your cluster can lose quorum and fence during upgrade to Citrix Hypervisor 8.0. To avoid this situation, either remove or add a server from your cluster to ensure that you have either one or three servers in your pool during the upgrade process. (CA-313222)

  • If you previously used the GFS2 feature as an experimental feature on XenServer 7.5 and haven’t updated to XenServer 7.6, complete the following steps when updating from XenServer 7.5 to Citrix Hypervisor 8.0:

    1. Export any data that you want to keep from these SRs.
    2. Detach and destroy any GFS2 SRs from your pool before upgrading.
    3. Disable clustering on your pool.
    4. Complete the update to Citrix Hypervisor 8.0.
    5. After the update completes, run the following command on all hosts in your pool:
    ```
    rm /var/opt/xapi-clusterd/db
    ```
    
    1. Run the following command on the pool master:

      systemctl restart xapi-clusterd
      
    2. When creating a GFS2 SR for your updated pool, ensure that you select Format and not Reattach. You cannot reattach a GFS2 SR that was created with XenServer 7.5 to a Citrix Hypervisor 8.0 pool. (CP-29465)

  • A GFS2 SR can raise a false ‘Failed to attach storage on server start’ alert, due to asynchronous plug of clustered storage. Check the SR status in XenCenter to determine whether the alert was a false positive. (CA-311625)

  • If you are using a GFS2 SR, ensure that you enable storage multipathing for maximum resiliency. If storage multipathing is not enabled, file system block writes might not fully complete in a timely manner. (CA-312678)

XenCenter

  • Changing the font size or dpi on the computer on which XenCenter is running can result in the user interface appearing incorrectly. The default font size is 96 dpi; Windows 8 and Windows 10 refer to this font size as 100%. (CA-45514) (CAR-1940)

  • When XenCenter is installed on Windows Server 2008 SP2, it can fail to connect to a Citrix Hypervisor host with the message “Could not create SSL/TLS secure channel”. To resolve this issue, ensure that one of the following Windows Updates is installed on the Windows Server 2008 SP2 system: KB4056564 or KB4019276. For more information, see http://support.microsoft.com/kb/4019276. (CA-298456)

  • Sometimes, the XenCenter storage live migration or the Import OVF/OVA wizard does not allow you to proceed and the Next button remains disabled. When this occurs, restart XenCenter and attempt the process again. (CA-314346)