DPM decreases CSV free disk space RRS feed

  • General discussion

  • Hi!

    Maybe there is a post about this already, but I want to bring this to your attention in case there's not.

    I had an issue with decreasing free disk space in my CSV, but no virtual machines, dump or paging files had grown. Disk space was swallowed rapidly by something and there was absolutely no new content or difference in size on the partition.

    It appeared that a VSS shadow had been left hanging and increasing for every new backup attempt. Running "VSSadmin delete shadows /all", only resulted in a error message saying something like: access is denied, let the backup software that initiated this also remove this.

    This was resolved by running DISKSHADOW -> DELETE SHADOWS ALL in an elevated command prompt on the Hyper-V host, and suddenly I got 500 GB of free disk space back.

    Just thought I should inform people (and MS) about this behaviour, since I have no contact with the developers directly. But again, this may be old news.

    Thursday, February 10, 2011 8:23 AM

All replies

  • Hi,

    As you accurately observed, somehow a snapshot did not get deleted, and using diskshadow to delete it was the right course of action - please monitor going forward to see if that happens again.  We have not seen that occur before, so I'm wondering if something other than DPM created it and left it dangling.  You can look at the date / time of the snapshot and see if that coinicides with a DPM  backup, and if so, was that backup successful or did it fail for some reason. 

    Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Saturday, February 12, 2011 6:31 PM
  • Hi and thanks for your reply!

    In this particular case (and only case so far) the virtual machine is running Exchange server and has the DPM remote agent installed. We take frequent backups of the mailbox databases from the VM and weekly backup of the entire vhd using Hyper-V VSS.

    While previous shadows stored in GUID path for that VM was corrupted, backups of that VM failed, kept on failing and increasing in size for every new backup attempt, until I deleted all the shadows. From there on it's been acting perfectly normal and all backups nowadays are successful.

    DPM is the only software using shadows in our environment.

    While I totally appreciate DPM handling it's own backup store, maybe it's time to extend the admin console to include shadow management, prune shadowcopies, co-location of data on tape and some more of the powershell features needed to properly manage DPM.

    Not making demands, merely a humble suggestion. To put even more GUI to the administration.

    Monday, February 14, 2011 2:06 PM