You cannot create a shadow storage area association between volumes when you use the Windows Server 2003 Volume Shadow Copy service

This article describes issues that you must consider when you use the Microsoft Windows Server 2003 Volume Shadow Copy service and the Shadow Copies of Shared Folders feature. Specifically, this article describes configuration issues that exist when the following conditions are true:

• You have volumes that are related through mount points.
• There is a cluster dependency between the associated disks of the volumes.

When you use the Shadow Copies of Shared Folders feature, you cannot create a shadow storage area association between volumes. This limitation exists if the volumes are related through mount points and there is a cluster dependency between their associated disks. The following rules apply:

• If there is a dependency between the mount point and the parent volume, the Shadow Copy configuration user interface might not let you configure a volume. This behavior occurs if the volume is mounted under the shadow-copied volume as the shadow storage area volume. For example, the shadow-copied volume C:\ should not have C:\MountPoint as its shadow storage area volume. The Volume Shadow Copy service does not let you add such a shadow storage area because it causes a dependency cycle.
  
  To elaborate on the example, when C:\Mountpoint is configured as the shadow storage area for volume C:\, the Volume Shadow Copy service makes volume C:\ dependent on C:\Mountpoint.
  • If C:\ was already dependent on C:\MountPoint, the dependency remains unchanged.
  • If C:\MountPoint was already dependent on C:\, the user interface does not let you add C:\MountPoint as the shadow storage area for C:\.
• If there is a dependency between the mount point and the parent volume, avoid configuring the parent volume of a mount point as the shadow storage area for the mount point. For example, avoid setting C:\ as the shadow storage volume for the C:\MountPoint volume. If you try to do this, and then later remove the shadow storage area settings, the Volume Shadow Copy service will silently remove the original dependency. This causes the mount point to no longer have the cluster dependency between C:\ and C:\MountPoint.
  
  For example, if you later remove C:\ as the shadow storage area for volume C:\MountPoint, the Volume Shadow Copy service removes the volume dependency between C:\MountPoint and C:\. Note that the dependency is removed even if it existed before you configured the shadow storage.

Note This article describes the concept of dependent volumes. Suppose that you have two volumes, volume X:\ and volume Y:\. You also have two shared disk cluster resources, Disk_Resource_X and Disk_Resource_Y. Volume X:\ has a dependency on volume Y:\ if the following conditions are true:

• Volume X:\ is located on shared disk resource Disk_Resource_X.
• Volume Y:\ is located on shared disk resource Disk_Resource_Y.
• Disk_Resource_X has a dependency on Disk_Resource_Y.

For additional information about using mount points with the Shadow Copy service, click the following article number to view the article in the Microsoft Knowledge Base: