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Cannot get consistent replicas of Hyper-V guests from one particular host (2008 R2 and DPM 2012 SP1) RRS feed

  • Question

  • DPM 2012 SP1 on Server 2008 R2. Hyper-V running on 2008 R2. Cannot get consistent replicas of Hyper-V guests from one particular host. (I have 4 hosts)

    Agent installs OK. Protection group can be created. Guests can be successfully backed up from within OS (wbadmin). Guests can be exported from host. Integration services up to date. Disk space OK (Host and Guest)

    What I can see that is different on my problem host:

    During DPM consistency check Event 33 VOL SNAP: The oldest shadow copy of volume D: was deleted to keep disk space usage for shadow copies of volume D: below the user defined limit.

    However there are no shadow copies managed by the Host OS on D: (D is the drive where the VMs are stored)

    Shadow copy settings on the problem host D: shadow copy is disabled but the space limit for shadow copy is 300MB.

    Shadow copy settings on D: on other hosts (which are OK): Shadow copy is disabled but the limits for disk space are much larger (57GB, 214 GB, 174GB)

    Could it be that somehow the host is deleting the shadow copies that DPM is creating before DPM has finished with them?

    Other information:

    On Host in event log:

    Volume Shadow Copy Service error: Volume/disk not connected or not found. Error context: DeviceIoControl(\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy54 - 000000000000014C,0x00560034,00000000001D6FF0,0,00000000001D5FE0,4096,[0]).

    Operation:

       Processing PreFinalCommitSnapshots

    Context:

       Execution Context: System Provider

    On host VSS writer after consistency check fail

    Writer name: 'Microsoft Hyper-V VSS Writer'

       Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}

       Writer Instance Id: {8b76c880-0091-46ef-a7ae-79e6d88a4e2f}

       State: [10] Failed

       Last error: Timed out

    Restarting Hyper-V VMMS clears this error.

    On problem host

    List Shadows tells me there are no shadow copies so I suppose the error must from the Guest.


    CarolChi

    Shadow copy settings on problem host

    Shadow copy settings on a host which is OK

    • Edited by Carol Chisholm Thursday, April 25, 2013 9:54 AM Added images
    Thursday, April 25, 2013 9:52 AM

Answers

  • In fact enabled Shadow Copies with a larger amount of space, and then disabled it.

    DPM seems to now be able to use the space as it needs.


    CarolChi

    Saturday, April 27, 2013 7:08 AM

All replies

  • Hi,

    <snip>
    Could it be that somehow the host is deleting the shadow copies that DPM is creating before DPM has finished with them?
    >snip<

    That is exactly what is occurring, so since the snapshots created for backup are temporary, you can safely resize the shadow copy storage on D:

    From an administrative command prompt on the problematic host run:

    vssadmin resize shadowstorage /for=d: /on=d: /maxsize=unbounded 


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    Saturday, April 27, 2013 1:31 AM
    Moderator
  • In fact enabled Shadow Copies with a larger amount of space, and then disabled it.

    DPM seems to now be able to use the space as it needs.


    CarolChi

    Saturday, April 27, 2013 7:08 AM