Client's SQL Server farm DBs are backed up by third-party tool that does not use VSS. About half of the instances show backups being made by some tool that is using VSS. I can disable SQL Server VSS Writer to stop these errant backups, but how do I track down what is running the VSS backups?

keywords: Volume Shadow Copy Service, volume-shadow-service [I don't have rep to create tags]

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    Kick off a server side trace. That will tell you who is doing what. Make sure to filter by the stuff that you only need.
    – Kin Shah
    Commented Oct 20, 2014 at 19:29
  • Kin, do you mean within SQL Server? That trace only shows that "SQL Server VSS Writer" is running the backup. How do I find what's telling VSS to do that? Or do you mean some other kind of trace? I'm experienced with SQL Server but don't know much about the OS.
    – Oliver
    Commented Oct 20, 2014 at 19:41
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    Yes I meant server side trace within SQL Server. If you want to track on OS level, I would recommend using sysinternals process explorer.
    – Kin Shah
    Commented Oct 20, 2014 at 19:45
  • In the SQL logs are you seeing things like (I/O Frozen, I/O Resume) at the time of these full backups?
    – Lawrage
    Commented Feb 9, 2016 at 6:51

1 Answer 1


I believe that if you run native SQL Server backups (using T-SQL BACKUP) instead of DPM protection agent-based SQL backups, the SQL Server VSS Writer service must not be used on your SQL Server database folders. (The same problem is true for other third-party backup tools.)

This DPM/VSS service is not used by native SQL backups. If you prevent the DPM protection agent backups from triggering SQL Server VSS snapshots, this will protect your chain of log backups.

If DPM/VSS does continue to backup the SQL Server files, then the log chain is broken, because there are two tools (T-SQL BACKUP and DPM/VSS) backing up the log files.

  • This would be true if VSS were making log backups. Whatever is using VSS is only making full backups, which does not break the chain.
    – Oliver
    Commented Oct 21, 2014 at 15:06

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