Server Backup and VSS RRS feed

  • Question

  • I had an issue where my backup target device, a 1.5TB USB drive, ran out of disk space. Looking at the disk properties in Disk Manager on the Server, I found that Shadow Copy was set to use all of my backup drive so I 'disabled' VSS on the backup drive. I immediately saw the disk space reclaimed. The downside is that I also lost all server backups. Now when I look at backup detail in the WHS2011 server console I can see that I do have backups since the time I disabled VSS. Here's my disk information on the Server:

    Disk 0

    No drive letter 100MB (boot partition), VSS disabled

    C- 60GB, VSS limited to 5GB

    D- (Data) 450 GB, VSS limited to 5GB

    Disk 1, 1.5 TB USB attached drive dedicated to backup

    No drive letter, VSS disabled

    Currently If I review the 'Details of backups' in Windows Server Backup I see the following:

    Destination Name EXTBU

    Capacity 1397 GB

    Total space used 270 GB

    Space used by backup items 212 GB

    Space used by backup copies 58 GB

    7 copies

    It appears that the problem is under control.

    It would be great if an expert could explain more about the relationship between Server backup and VSS on the backup target device.

    Best Regards,


    Tuesday, March 6, 2012 1:06 PM

All replies

  • tl;dr: Turn VSS back on for your backup drive, because it's required.

    Windows Home Server 2011 uses the same backup engine that Windows Server 2008 R2 does. That engine backs data up into a "differencing" VHD. "Differencing" is implemented using VSS, so when you turned it off, VSS discarded all snapshots on the drive, and thus all backups. I honestly can't tell you if you actually have good backups right now, but I kind of doubt it. You can learn more about server backup on Technet (or a host of other non-Microsoft sites); as I said, the engine in Windows Home Server is inherited from the base OS.

    I'm not on the WHS team, I just post a lot. :)

    Tuesday, March 6, 2012 4:53 PM