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Unable to back up boot partition on Vista PC RRS feed

  • Question

  • Hi, everyone - new installation of WHS and just working the bugs out of backing up and restoring PCs. On one of my Vista PCs I am able to back up all of the partitions except for the boot partition. If I attempt to, the backup will time out and fail with "The computer failed to take a snapshot of the volume for backup". Vista event log shows:
    Backup set 2 on SERVER failed: Microsoft.HomeServer.Backup.VSS.ShadowVolumeException: VSS Operation timed out ---> System.TimeoutException: VSS Operation timed out
       at Microsoft.HomeServer.Backup.VSS.ShadowVolumeSet.Wait(IVssAsync va)
       at Microsoft.HomeServer.Backup.VSS.ShadowVolumeSet.CreateShadowVolume(VolumeInfo[] volumes)
       --- End of inner exception stack trace ---
       at Microsoft.HomeServer.Backup.VSS.ShadowVolumeSet.CreateShadowVolume(VolumeInfo[] volumes)
       at Microsoft.HomeServer.Backup.VSS.ShadowVolumeSet..ctor(VolumeInfo[] volumes)
    
    Running vssadmin list writers shows eight registered writers, all listed as stable, no error . Running chkdsk F: /f on the boot partition does not show any errors; I even checked the partition while booted from a Vista recovery CD to a command prompt. Backing up any other partition on the machine works great except this one.

    Now for the oddities in my Vista machine setup - I have a separate boot partition with a different cluster size than the main Vista partition. My layout is as follows:

    [C: (Vista), primary1, NTFS, 16 kB clusters, 50 GB] [D: (Data), primary2, NTFS, 16 kB clusters, 30 GB] [E: (Data2), primary3, NTFS, 16 kB clusters, 68.5 GB] [F: (Boot), primary4, NTFS, 4 kB clusters , 0.5 GB]

    Oddity #2 is that whenever I run chkdsk on the boot partition from Windows, the program displays a "volume is in use by another process" message. This message is NOT displayed when checking the other 3 partitions:
    C:\Windows\system32>chkdsk f:
    The type of the file system is NTFS.
    The volume is in use by another process. Chkdsk
    might report errors when no corruption is present.
    Volume label is Boot.
    However, my work PC (not the one in question) also displays the same message when doing chkdsk on its boot partition.

    I am wondering if whatever process is locking this partition also prevents VSS from running and thus the WHS backup from succeeding? Again, WHS backup works perfectly on the other three partitions.

    Any ideas?
    Wednesday, July 22, 2009 6:18 PM

Answers

  • Ken:

    In case you run into this again, it is a free space issue. VSS requires a minimum of 300 MB free space on a partition. In one of those DOH! moments I read the VSS documentation and found this. I freed up 400 MB on the boot partition and the backup succeeded.
    • Marked as answer by Mark Wharton Wednesday, July 22, 2009 11:47 PM
    Wednesday, July 22, 2009 11:47 PM

All replies

  • Please run chkdsk /r on the boot partition, then reboot when prompted. After chkdsk finishes and the PC has finished the boot sequence, you'll find a report of what chkdsk found and fixed in your application log; the source will be winlogon.

    It's also possible that the partition is just too small to take a snapshot...

    I'm not on the WHS team, I just post a lot. :)
    Wednesday, July 22, 2009 7:03 PM
    Moderator
  • Ken:

    Forgot to mention that I have also done chkdsk /r and there were no bad sectors or other file system errors.

    I also wonder if there is a minimum partition size to take a snapshot. I noted that when I was backing up the other partitions (which had Vista shadow copy storage filled to the max), that there were volsnap messages in the logs indicating that when WHS ran a backup, some of the shadow copy files were being deleted to make additional room. So, does the WHS backup store info in the shadow copy storage area on the partition being backed up? If it does, then I can understand what might be going on with the boot partition. It's a 512 MB partition that has 150 MB of free space, so there may not be enough room for whatever WHS needs for the snapshot.

    I suppose I could test that theory by resizing the partition up to 1 GB, for example. Does this sound plausible?
    Wednesday, July 22, 2009 7:38 PM
  • I have encountered anecdotal evidence in the past that there's a minimum size for VSS to function on a volume. And if VSS doesn't function on a volume (for whatever reason), it's impossible for Windows Home Server to back up that volume, because it needs to back up a consistent "slice" of the volume and that's what VSS gives it.

    You can try resizing it and then reconfiguring backups on that machine.

    I'm not on the WHS team, I just post a lot. :)
    Wednesday, July 22, 2009 7:59 PM
    Moderator
  • Since we don't know whether it is a free space issue or an absolute size issue, I will do the test this way and then post the results:

    1. Remove files from the boot partition leaving more free space. I have a copy of VistaPE in there, so if I remove that temporarily there will be over 400 MB free on a 512 MB partition.
    2. If that doesn't work, I will resize the partition to 1 GB

    Wednesday, July 22, 2009 8:14 PM
  • Ken:

    In case you run into this again, it is a free space issue. VSS requires a minimum of 300 MB free space on a partition. In one of those DOH! moments I read the VSS documentation and found this. I freed up 400 MB on the boot partition and the backup succeeded.
    • Marked as answer by Mark Wharton Wednesday, July 22, 2009 11:47 PM
    Wednesday, July 22, 2009 11:47 PM
  • Hmm. I thought the minimum required free space was a percentage of the drive. I guess I need to go reread the VSS documentation myself. Glad you've got it sorted, but I would still recommend resizing the partition so you can put back what you feel you need...
    I'm not on the WHS team, I just post a lot. :)
    Thursday, July 23, 2009 3:56 PM
    Moderator
  • Ken:

    Yes, did that. I resized the partition larger by 300 MB and put back the VistaPE files that were removed as a test and all is well.

    There may be a secondary consideration for the space required for VSS to work, but the 300 MB is an absolute lower limit. If you run vssadmin resize ShadowStorage -help on a Vista or Win7 box you will see in the help text "...MaxSizeSpec must be 300MB or greater and accepts the following suffixes:..."

    This brings up an interesting point that may result in problems for people trying to back up a Windows 7 PC with WHS. The default installer will create a separate 100 MB boot partition that is not given a drive letter and install Win7's boot files (bootmgr and the /Boot folder) to the small partition, while installing the rest of Windows 7 to a larger, visible partition. What will happen to people who want to back up their entire disk on a Windows 7 machine? VSS will fail on the 100 MB boot partition and if this partition is included in the backup then WHS backup will fail.
    Thursday, July 23, 2009 4:22 PM
  • Mark, the boot partition backs up on a Windows 7 RC installation, and restores successfully. There may be differences in VSS in Windows 7 that allow this scenario to work, or it may be something about your particular environment that prevented it from working. But it does work in Windows 7
    I'm not on the WHS team, I just post a lot. :)
    Friday, July 24, 2009 3:18 PM
    Moderator