Share via


Event ID 25 — Diff Area Integrity

Applies To: Windows Server 2008 R2

The Diff Area is the storage space that Shadow Copies of Shared Folders allocates on a volume for maintaining the snapshots of the contents of shared folders. A snapshot is a block-level set of information that represents the differences between the current content and content from a previous point in time. The integrity of existing and new snapshots depends on the integrity of the Diff Area.

Event Details

Product: Windows Operating System
ID: 25
Source: VolSnap
Version: 6.1
Symbolic Name: VS_ABORT_SNAPSHOTS_OUT_OF_DIFF_AREA
Message: The shadow copies of volume %2 were aborted because the diff area file could not grow in time.  Consider reducing the IO load on this system to avoid this problem in the future.

Resolve

Move the Diff Area to a volume on a different disk

Select a volume on a different disk as the storage area for shadow copies to eliminate the possibility that high I/O load on the disk will cause shadow copies to fail. This configuration also provides better performance. This is the recommended configuration for heavily used file servers.

To perform this procedure, you must have membership in Administrators, or you must have been delegated the appropriate authority.

To move the Diff Area to a volume on a different disk:

Caution: When you change the location of the Diff Area, all previous shadow copies are deleted.

  1. Click Start, and then click Computer.

  2. Right-click any of the volumes listed, and then click Configure Shadow Copies. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.

  3. Click the volume for which the shadow copy failed, and then click Settings.

    Note: If shadow copies of the volume are enabled, you must first disable them by clicking the volume, and then clicking Disable.

  4. Set the Diff Area to a volume on a different disk by selecting the volume from the drop-down list under Storage area, and then click OK.

  5. Verify that the volume is still selected, and click Enable. If you are asked to confirm that you want to enable shadow copies, click Yes.

  6. Click OK to exit.

Verify

The Diff Area is working correctly if a new shadow copy can be successfully created.

To perform this procedure, you must have membership in Administrators, or you must have been delegated the appropriate authority.

To create a new shadow copy:

  1. Click Start, and then click Computer.

  2. Right-click any of the volumes listed, and then click Configure Shadow Copies. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.

  3. Click the volume that you want to create a new shadow copy of, and then click Create Now. The Diff Area is working correctly if the new shadow copy is listed under Shadow copies of selected volume.

    Note: Depending on the size of the volume and the number of changes that have occurred since the last shadow copy, creating the new shadow copy can take a few seconds or several minutes.

Diff Area Integrity

File Services