Determining storage options for shadow copies

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Determining storage options for shadow copies

Before deploying Shadow Copies of Shared Folders, it is recommended that you create a plan that specifies where the shadow copies will be stored and what the storage limits will be.

The minimum amount of storage space that you can specify is 300 megabytes (MB). The default storage size is 10% of the source volume (the volume being copied). If the shadow copies are stored on a separate volume, change the default to reflect the space available on the storage volume instead of the source volume. Remember that when the storage limit is reached, older versions of the shadow copies will be deleted and cannot be restored.

When determining the amount of space to allocate for storing shadow copies, you must consider both the number and size of files that are being copied, as well as the frequency of changes between copies. For example, 100 files that only change monthly require less storage space than 10 files that change daily.

Remember that to change the storage volume, you must delete the shadow copies. If you delete shadow copies, you lose the existing file change history that is kept on the original storage volume. To avoid this problem, verify that the storage volume that you initially select is large enough to handle your growing business needs.


  • There is a limit of 64 shadow copies that can be stored on a volume. When this limit is reached, the oldest shadow copy is deleted and cannot be retrieved.

    For more information, see Change the settings for Shadow Copies of Shared Folders.

  • If you are using a basic disk as a storage area for shadow copies and you intend to convert the disk into a dynamic disk, it is important to take the following precaution to avoid data loss. If the disk is a non-boot volume and is a different volume from where the original files reside, you must first dismount and take offline the volume containing the original files before you convert the disk containing shadow copies to a dynamic disk. You must bring the volume containing the original files back online within 20 minutes, otherwise, you will lose the data stored in the existing shadow copies. If the shadow copies are located on a boot volume, you can convert the disk to dynamic without losing shadow copies.

    You can use the mountvol command with the /p option to dismount the volume and take it offline. You can mount the volume and bring it online using the mountvol command or the Disk Management snap-in.


  • For information about enabling shadow copies in a server cluster, see Enable Shadow Copies for Shared Folders in a cluster. Do not use Cluster Administrator or cluster.exe to make changes to the settings or schedule for shadow copies of shared folders; use the shadow copies interface instead.