When you create a shadow copy backup on a Microsoft Windows Server 2003-based computer, an Error event that is similar to the following is logged in the System log:
Event Type: Error
Event Source: VolSnap
Event ID: 21
Description: The flush and hold operation for volume F:SG2-Log was aborted because of low available system memory.
This problem occurs because the available system memory is low. The low system memory is caused by disk fragmentation.
Note This problem usually occurs only when the /3GB switch is set in the Boot.ini file.
To resolve this problem, obtain the latest service pack for Windows Server 2003. (SP2)