We recommend that you consider the following best practices when you work with Shadow Copies of Shared Folders.
Use a separate volume on another disk as the storage area for shadow copies.
- 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. For
failover clusters, this configuration also requires that the
original volume and storage volume belong to the same cluster
If you are using failover clusters, two volumes on the same disk cannot be associated for diff area storage.
- This is because the cluster manages the disk
for online and offline operations, but the Volume Shadow Copy
Service (VSS) needs to have the diff area and original volumes
brought offline or online in a specific order. Instead, the storage
volume and the original volume need to be the same volume, or they
need to be on separate physical disks.
Consider how your clients will use a shared resource before you enable Shadow Copies of Shared Folders and set scheduling options.
- Adjust the shadow copy schedule to fit the
work patterns of your clients.
Do not enable shadow copies on volumes that use mount points.
- The mounted drive will not be included when
shadow copies are created. 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. Alternatively, you can
explicitly include the mounted volume in the schedule for shadow
copy creation. (For previous versions of a file to be available,
the volume must have a drive letter assigned.)
Perform regular backups of your file server.
- Shadow Copies of Shared Folders is not a
replacement for performing regular backups. Use a backup utility,
such as Windows Server Backup in Windows Server 2008 or
Windows Server 2008 R2, in coordination with Shadow
Copies of Shared Folders as your strategy for data protection.
Do not schedule copies to occur more often than once per hour.
- The default schedule for creating shadow
copies is at 7:00 A.M., Monday through Friday. If you decide that
you need copies to be created more often, verify that you have
allotted enough storage space and that you do not create 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 created too often, this limit
might be reached very quickly, and older copies could be lost at a
Before deleting a volume that is being shadow copied, delete the scheduled task for creating shadow copies.
- 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. To manually delete the scheduled task, click Start,
point to Administrative Tools, and then click Task
Scheduler. In Task Scheduler, click Task Scheduler
Library, right-click the task to create shadow copies, and then
Use an allocation unit size of 16 kilobytes (KB) or larger when formatting a source volume on which Shadow Copies of Shared Folders will be enabled.
- 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