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Why virtual servers are migrating

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  • Why virtual servers are migrating

    Hi Folks
    I am new here as google etc did not point anywhere. I've got a 2-node cluster based on 2008 R2 with 2 SANs attached. 1 is purely for the data 2nd is very small and is a boot LUN.

    When building a cluster i did not maybe noticed but now I see that all my virtual machines reside on a single node. I would like to spread the load across both physical boxes. Unfortunately, whichever type of migration I run for any of the V-boxes - move, live migrate or quick, all of them are shutting down and then move across. I know it is weird but cluster verifies all of the cluster config fine.
    I need that load spread - that's why I think you've got the cluster....
    any help appreciated as I need to add 2 more servers and will be pretty tight on RAM for those.
    thanks in advance

  • #2
    Re: Why virtual servers are migrating

    BTW - have checked and all v-boxes are able to failback onto both nodes and do not have the same node as default
    I think I have gone through all setting/properties of the servers
    any ideas


    • #3
      Re: Why virtual servers are migrating

      So this is Hyper-V? If you don't want downtime, you would use Live Migration and for that, the VMs would need to sit on a CSV volume that is visible by both servers and of course you would enable the VM for HA. If it is migration to a different SAN volume or you are not using a CSV volume and depending on the configuration, the VM will then potentially shutdown and then migrate.

      If you can provide additional information and/or sceen shots of your configuration.


      • #4
        Re: Why virtual servers are migrating

        If Live Migration is an option then things shouldn't go down during the migration. For quick and storage migrations Hyper-V will save the VM state to make the final data copy, VM tare-down, bring services up on destination server, etc.

        If you haven't configured CSVs then you probably should as this is the easiest way to manage HA. It is possible to do Live Migrations without CSV but it requires all VMs have their own LUN(s).

        If your VMs are shutting down during the migration then something is very wrong. They should never shutdown but all migrations besides Live will save the VM state.

        Could you explain your SAN setup in more detail? When you say you have two SANs attached, do you mean two LUNs? And if you mean LUNs, are both servers attached to the same two LUNs or their own two LUNs? Could also explain what the small boot LUN is for? Are the VMs booting off this LUN? Is it the cluster witness?

        With that info we might be better able to explain what's going on.

        Network Consultant/Engineer
        Baltimore - Washington area and beyond


        • #5
          Re: Why virtual servers are migrating

          Many thanks Jeremy

          that sounds like a plan - although my virtual guests are on the CSVs spread on 2 separate LUNs I lack the virtual network added to link only them. From what I gather this should be an additional network but in a private mode as another VLAN?
          many thanks


          • #6
            Re: Why virtual servers are migrating

            here it is more in details

            3 physical boxes linked with MPIO to each SAN's LUNs.

            LUNs are for:
            user data,
            Cluster Quorum
            2 Boot LUNs off which the virtual servers are booting up.

            All those are configured as CSVs. The additional drives for the guest machines are added from the CSV pool.
            hope that helps



            • #7
              Re: Why virtual servers are migrating

              Sorry but could you clarify? All the LUNs can't be CSVs if one of them is for quorum. But in a 3 node cluster you shouldn't have a witness disk.

              So, I'm guessing that:
              - You have a 3 node cluster
              - there are 6 LUNs that are connected to each host and those LUNs are added to the cluster storage?
              - there are 2 storage arrays?

              Could you verify or correct the information above?
              Of the LUNs connected to the cluster storage, how many are configured as CSVs?
              Also, how many networks are configured on the cluster?
              On the 3 hosts, have you configured identical virtual networks? (they should all be External unless you need some test networks that are isolated)

              Network Consultant/Engineer
              Baltimore - Washington area and beyond