One of the biggest enhancements of XenServer 6.2 is performance. Citrix claims a density improvement of about 4 to 5 times compared to XenServer 6.1. So it’s worth to test this. I have a customer with XenServer 6.0.2 who is using Citrix Provisioning Services 6.1 to enroll XenApp servers. We already tried to upgrade to XenServer 6.1, but this resulted in BSOD on the XenApp servers. Citrix PVS 6.1 was not supported on XenServer 6.1. But now there are hotfixes available for PVS 6.1 that should make it work. So let’s give it a try.
I installed a clean XenServer 6.2 host and built a new master image in PVS 6.1 with the latest XenServer 6.2 tools. After installing the release version of the PVS 6.1 target software we still get a BSOD after booting from vDisk, which was to be expected. But after applying hotfix CPVS61016 the PVS machine boots correctly. This hotfix contains a new PVS_Device_x64.exe target software installer. First remove the older PVS target software and then reinstall the new one. We did not apply the PVS server side updates, because this is a stable production environment which is running fine.
When running the new XenApp PVS VMs on XenServer 6.2, the performance improvement was really amazing. The logon process is much faster and application response is much better. XenServer 6.2 is really a giant leap forward.
So we decided to upgrade a production server with XenServer 6.0.2 to XenServer 6.2. We had already built the PVS master image on the XenServer 6.2 testserver, so we could use that. After upgrading the first XenServer production host we changed the vDisk of a vm in the PVS console to the new vDisk version for XenServer 6.2. And then… BSOD, the XenApp server did not want to boot from the new vDisk. The same vDisk proved to work on the testserver with XenServer 6.2. How did this happen?
The problem is that the vm on the upgraded XenServer is marked with legacy tools by the upgrade process of XenServer. But because we boot from a vDisk, the vm suddenly is starting with the latest XenServer tools and not with the legacy tools, which does not match with the vm settings. We have two options to correct this:
Change the vm parameter with the command: xe vm-param-set uuid= platform:device_id=0002. A vm with legacy tools has device_id=0001.
Or recreate the vm.
We decided to recreate the vm to make sure we get rid of all the legacy stuff.
So to summarize, XenServer 6.2 is really a great step to improve the performance. PVS 6.1 VMs can run fine on XenServer 6.2, but you have to use the target software from hotfix 016. After upgrading XenServer, you have to adjust the VM device parameter or recreate the VM.