Best Practices for Shadow Copies of Shared Folders

Updated: May 29, 2013

Applies To: Windows Server 2008, Windows Server 2012, Windows Server 2012 R2

We recommend that you consider the following best practices when you work with Shadow Copies of Shared Folders.

  • Select a storage area on a disk that is not being shadow copied. Using a separate volume on another disk eliminates the possibility that high I/O load will cause shadow copies to be deleted and provides better performance. This is the recommended configuration for heavily used file servers.

  • The mounted drive will not be included when shadow copies are taken. Enable shadow copies only on volumes without mount points or when you do not want the shared resources on the mounted volume to be shadow copied.

  • Shadow Copies of Shared Folders is not a replacement for performing regular backups. Use a backup utility in coordination with Shadow Copies of Shared Folders as your best preparation for restoring.

  • The default schedule for creating shadow copies is at 7:00 A.M. and noon, Monday through Friday. If you decide that you need copies to be taken more often, verify that you have allotted enough storage space and that you do not take copies so often that server performance degrades. There is also an upper limit of 64 copies per volume that can be stored before the oldest copy is deleted. If shadow copies are taken too often, this limit might be reached very quickly, and older copies could be lost at a rapid rate.

  • If the volume is deleted without deleting the shadow copy task, the scheduled task will fail and an Event ID: 7001 error will be written to the event log. Delete the task before deleting the volume to avoid filling the event log with these errors.

  • If you plan to defragment the source volume on which Shadow Copies of Shared Folders is enabled, we recommend that you set the cluster allocation unit size to be 16 KB or larger when you initially format the source volume. If you do not, the number of changes caused by defragmentation can cause previous versions of files to be deleted.

  • If you require NTFS file compression on the source volume, you cannot use an allocation unit size larger than 4 KB. In this case, when you defragment a volume that is very fragmented, you may lose older shadow copies faster than expected.

  • After backing up a volume that contains shadow copies, do not restore the volume to a different volume on the same computer as this will leave multiple snapshots with the same Snapshot ID on the system and will cause unpredictable results when performing a shadow copy revert.

  • You can restore the volume to the original volume on the same computer; you can restore the volume to a different volume on a different computer, or you can restore file and folders to any location on the same computer.

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