Backup jobs fail due to VSS errors if the drive being backed up is under a heavy load. The job log may indicated that corrupt data was encountered.

Problem

Backup jobs fail due to VSS errors if the drive being backed up is under a heavy load.

Error Message

VOLSNAP  error from the System log of the Event Viewer:
Event ID:  25
The shadow copies of volume D: were deleted because the shadow copy storage could not grow in time. Consider reducing the I\O load on the system or choose a shadow copy storage volume that is not being shadow copied.

The Application log of the Event Viewer may show events wtih the source "Backup Exec" with Event ID 57481, 57484, and/or 57476.

The Backup Exec job log may report:
WARNING: <file name> is a corrupt file. This file cannot verify.
 

Final error: 0xe000fe36 - Corrupt data encountered. See the job log for details.
Final error category: Resource Errors

For additional information regarding this error refer to link V-79-57344-65078

UMI Code: V-379-34113

Cause

Microsoft Volume Shadow Copy Service (VSS) is part of the Windows operating system.  When Backup Exec is used to backup a volume with the Advanced Open File Option, or when a backup is created for a VSS aware application, Backup Exec calls VSS at the beginning of the job to take a snapshot of the volume. This snapshot is also known as a shadow copy, and is supposed to persist for the duration of the backup of the volume.  However, the above errors indicate that the I/O load on the drive being backed up was too high.  Because of this high load on the drive, VSS encountered a failure and deleted the shadow copy snapshot from which Backup Exec was backing up prior to the end of the job. The corrupt data message is shown in the Backup Exec job logs as it tries to read open files through the shadow copy that was destroyed. 

By default VSS is configured to write the shadow copies of a volume to a storage location on the volume itself. This can result in very high I/O during the backup of a volume since the drive is experiencing load from the backup reading files, load from VSS reading from and writing to the shadow copy, and load from any other applications on the system using that same volume.

Solution

The solution is to configure VSS to write the shadow copies of the problem drive to a different drive which has more available space and less load during the backup. The ideal situation would be to have a separate drive dedicated to shadow copies that is not being backed up and is also not the drive containing the paging file.  If this is not possible, specifying a separate drive that contains the paging file is typically still better than storing the shadow copies on the drive being backed up.

The instructions in the related articles below are operating system specific and show how to configure the shadow copy storage location of a volume to go to a different volume.

Certain snapshot provider services have been found to interfere with a System State or Shadow Copy Component backup:

Check the writers on the affected server. If the File Server Resource Manager or Windows Deployment Services are running, disable the services.