Hyperv Failovercluster Live Migration only possible after I fast moved in shutdown state until I shutdown the system

47kOverlord 0 Reputation points
2023-05-23T13:47:20.1+00:00

Hey guys

I have a strange behavior with a system I added to my Windows Server Hyper-V Failover Cluster in Server 2022.

The servers have nearly the same configuration - the CPUs are a Intel Xeon Gold and Intel Xeon Silver:

Cluster with Server 1 and Server 2 (the new Server).

Behavior not working:

  • VM is on Server1 and I want to Live Migrate to Server 2
    • not working, because of "processor specific features" - but the CPU compatibility mode from the VM is activated

Behavior working:

  • If I shutdown the VM and do a fast failover from Server 1 to Server 2 it's working - and I can start and work with the VM
  • If I do then a failover from Server 2 to Server 1 it's working
  • A switch back from Server 1 to Server 2 is working as well
  • When the VM is on Server 2 I can restart and shutdown the VM and after starting again I'm able to live migrate to Server 1

At this point it's not working anymore:

  • When I shutdown or restart the VM on Server 1, I'm not able to do a failover to Server 2 (see behavior not working - processor specific features)

Where is the difference? Why is the normal failover working as long as the machine is moved in shutdown state and failovered while it's running until it's shutdown/restart on a different server (Server 1).

I found something about Bios/Driver differences but since both servers are not equal, I have differences.

Greetz

Ovrld

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  1. Limitless Technology 44,116 Reputation points
    2023-05-24T11:09:30.79+00:00

    Hello

    Thank you for your question and reaching out.

    To see if it operates the same way, I would first create a brand-new virtual machine. This is because sometimes the faults are with the VMs themselves rather than the hypervisor. Additionally, make an effort to verify that the Hyper-V settings on both hosts are identical.

    Also run Cluster validation wizard to verify cluster health is in Good state.

    --If the reply is helpful, please Upvote and Accept as answer--

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  2. 47kOverlord 0 Reputation points
    2023-05-25T10:00:05.3133333+00:00

    Thank you for your help - I created a new machine from scratch on the Server1, but I had the same issues.

    Server1 and Server2 have the same settings in Hyper-V Manager.

    I understand that there could be an issue with live migration - but why is there no issue when I move the machine to the Server2, start it there and I'm able then to live migrate?

    Edit:

    Here's the CPU difference:

    XeonSilver:

    Instructions sets: MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, EM64T, AES, AVX, AVX2, AVX512F, FMA3

    Microcode Revision: 0x5003501

    XeonGold:

    Instructions sets: MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, EM64T, AES, AVX, AVX2, AVX512F, FMA3, TSX, SHA

    Microcode Revision: 0xD000389

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  3. 47kOverlord 0 Reputation points
    2023-05-26T09:23:57.9066667+00:00

    Ok got it!

    https://learn.microsoft.com/en-us/windows-server/virtualization/hyper-v/manage/manage-hyper-v-scheduler-types

    I made an In-Place upgrade before (yes I know) and the scheduler type was set to Servers 2016 (Classic) and not to Core (since 2019). This was the reason.

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