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DPM failed to fixup VHD parent locator post backup...

    Question

  • Hi,

    Having been backing up various VMs on a Hyper-V box for months without any problems, I'm suddenly receiving this error:

    "DPM failed to fixup VHD parent locator post backup for Microsoft Hyper-V\Backup Using Child Partition ShapShot\Exchange on hyperv.domain.dom.  Your recovery point is valid, but you will be unable to perform item-level recoveries using this recovery point. (ID 3130)".

    It says I can safely dismiss the alert if I don't need item level restores but, if I do, then I need to install the Hyper-V role on the DPM server.  Why do I need to do this all of a sudden?

    The one thing that strikes me as more than a coincidence is that I installed Update Rollup 4 on the Exchange 2010 server to which this alert relates at the end of last week and this is the first backup schedule that's executed since then.  Has the rollup changed something in Exchange that now requires Hyper-V to be installed on DPM?


    Toby
    Monday, July 26, 2010 2:29 PM

Answers

  • Right, might be on to something.

    In a bit of an "RTFM" moment, I thought I'd re-check the the "More Information" link in the warning alert in the DPM console.  This time I noticed a link at the bottom to a KB article which I hadn't spotted before, namely this one:

    http://support.microsoft.com/kb/971677

    This appears to be very relevant to my situation as my DPM server is on Server 2008 SP2 whilst the Hyper-V server is 2008 R2.  Also, I presume the differencing disk referred to in the article is what is created when the snapshot system is used.  Thinking about it, it seems that the only VMs affected by this issue are those where I've created a snapshot, even if that snapshot has later been deleted.

    Have requested the Hotfix so will install it and report back ASAP.


    Toby
    Monday, August 16, 2010 9:04 AM

All replies

  • To perform item level recovery DPM 2010 needs to mount the vhd on the DPM server and then expose the underlying volumes. To mount the vhds of a VM DPM relies on Hyper-V wmi calls. This support is only available if Hyper-V role is installed on the DPM server and hence you need to install the Hyper-V role. If you don't install the Hyper-V role you can still backup and recover the VM as a unit.


    Thanks Shyama Hembram[MSFT] This posting is provided AS IS, with no warranties, and confers no rights.
    Monday, July 26, 2010 3:56 PM
    Moderator
  • Hi, thanks for the reply.

    I'd actually forgotten but the DPM server does actually have the Hyper-V role already installed which just adds to the weirdness.


    Toby
    Tuesday, July 27, 2010 7:31 AM
  • Just got this warning alert again, does anyone have any more ideas on this?  Only seems to be affecting my Exchange VM and happening post Rollup 4.
    Toby
    Monday, August 2, 2010 7:58 AM
  • Can I get some more help on this if possible please?

    This particular VM is only one of many.  They were all backing up without issue prior to Rollup4 being installed on the Exchange box and now only the Exchange one is consistently producing this error so I have to believe the Rollup is the culprit.

    Have just tried removing the Exchange server from the protection group and re-adding it but the error has appeared immediately.  Really need to get this sorted.

    Many thanks.


    Toby
    Monday, August 9, 2010 4:40 PM
  • Check to see if you have any Hyper-V snapshots for that guest.  It may be that someone took a guest snapshot prior to installing the Exchange rollup-4.  Now that should not cause this problem IF you have the hyper-v roll installed on the DPM server and have rebooted after installing the roll, but it may be causing the alert and if so, deleting the snapshot and restarting the guest should eliminate it.
    Regards, Mike J [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Wednesday, August 11, 2010 10:12 PM
    Moderator
  • Hi Mike,

    I did create a snapshot prior to installing the Rollup but, as soon as I'd verified everything was ok, I deleted the snapshot.  I'm not entirely sure whether I've rebooted the Exchange VM since the snapshot was deleted - could this be causing the issues?  The server has a load of updates pending from this week's prolific "patch Tuesday" so I'll apply these and get the box rebooted a bit later to see if it helps.


    Toby
    Thursday, August 12, 2010 7:26 AM
  • Yes, it could be.  The snapshot does not really get deleted until you shutdown the guest, so shut it down completly, then restart it and see if that resolves the issue.
    Regards, Mike J [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Thursday, August 12, 2010 6:45 PM
    Moderator
  • Well I'm afraid that didn't work :(

    I'm also now getting the exact same error on another VM, this time a plan old Windows XP one, so it's possibly not related to the Exchange Rollup, although something's obviously changed.

    Anyone else have any suggestions? :(


    Toby
    Sunday, August 15, 2010 1:07 PM
  • Right, might be on to something.

    In a bit of an "RTFM" moment, I thought I'd re-check the the "More Information" link in the warning alert in the DPM console.  This time I noticed a link at the bottom to a KB article which I hadn't spotted before, namely this one:

    http://support.microsoft.com/kb/971677

    This appears to be very relevant to my situation as my DPM server is on Server 2008 SP2 whilst the Hyper-V server is 2008 R2.  Also, I presume the differencing disk referred to in the article is what is created when the snapshot system is used.  Thinking about it, it seems that the only VMs affected by this issue are those where I've created a snapshot, even if that snapshot has later been deleted.

    Have requested the Hotfix so will install it and report back ASAP.


    Toby
    Monday, August 16, 2010 9:04 AM
  • Yep that's cured it!

    Thanks again Mike for pointing me in the right direction - it was indeed the snapshots that were at the root of it all.


    Toby
    Monday, August 16, 2010 9:46 AM
  • Nice catch !!
    Regards, Mike J [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Tuesday, August 17, 2010 12:58 AM
    Moderator