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Hyper-V Host Lost Power

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  • Hyper-V Host Lost Power

    I have been searching online to figure out how Server 2008 with Hyper-v handles a physical power outage. There was a recent concern with how Hyper-V Guests handle the host being shutdown/dropped.

    As in, if the host server were to have some sort of catastrophic crash and go down in a blaze of glory what would happen to the VMs? Assuming the hard drives aren't toast and I can still recover the the VHDs. Are they up to the minute or at the last snapshot??


  • #2
    Re: Hyper-V Host Lost Power

    Surely you have a UPS and a graceful shutdown?

    If not, they will be up to last written data, which may be more recent than the snapshot
    Tom Jones
    MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
    IT Trainer / Consultant
    Ossian Ltd

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    • #3
      Re: Hyper-V Host Lost Power

      Yes, I do have my hyper-v server setup with UPS and redudant power supplies. I was asked what would happen if it "went down" and not gracefully how it would react. We use a lot of VMWare ESX and im told that they revert back to the last snapshot and don't write continuously. I dont know, that is what im told.


      • #4
        Re: Hyper-V Host Lost Power

        I can tell you from my sad recent experience that the VMs will restart exactly as a physical server would.
        In the last two weeks we had twice a severe power outage in our servers' room, both in the middle of the night. Even the six hours the UPS held on weren't enough...
        Anyway, all the VMs (I have 14 of them, running on different hosts) started exactly the same like the physical servers.
        I have to say that I don't have no databases running on them, so I don't have to deal with inconsistency.
        Another thing: nor VMWare , neither Microsoft suggest using snapshots in production environments other than for short-term backups... So use them with caution...

        Sorin Solomon

        In order to succeed, your desire for success should be greater than your fear of failure.


        • #5
          Re: Hyper-V Host Lost Power

          Originally posted by sorinso View Post
          I can tell you from my sad recent experience that the VMs will restart exactly as a physical server would.
          I second that.

          In addition, my co-worker managed to crash our shiny six-node Hyper-V cluster, which resulted in unexpected power-downs. The VMs were quite okay, but System Center Virtual Machine Manager went haywreck. Some guests were duplicated and the only way to get rid of those were either to delete both instances or store one into the library. Not a nice situation.



          • #6
            Re: Hyper-V Host Lost Power

            I agree with sorinso. I have a couple Hyper V servers running. The one Host server kept blue screening and restarting. The Virtual server treated as if it was an unexpected shutdaown.