Determining Creation Frequency; Shadow Copies And Drive Defragmentation; Mounted Drives; Managing Shadow Copies - HP StoreEasy 1000 Storage Administrator's Manual

By keeping the shadow copy on the same volume, there is a potential gain in ease of setup and
maintenance; however, there may be a reduction in performance and reliability.
CAUTION:
of disk input/output (I/O) can cause all shadow copies to be deleted. If the sudden deletion of
shadow copies is unacceptable to administrators or end users, it is best to use a separate volume
on separate disks to store shadow copies.

Determining creation frequency

The more frequently shadow copies are created, the more likely that end users will get the version
that they want. However, with a maximum of 64 shadow copies per volume, there is a trade-off
between the frequency of making shadow copies and the amount of time that the earlier files will
be available.
By default, the storage system creates shadow copies at 0700 and 1200, Monday through Friday.
However, these settings are easily modified by the administrator so that the shadow copy schedule
can better accommodate end user needs.

Shadow copies and drive defragmentation

When running Disk Defragmenter on a volume with shadow copies activated, all or some of the
shadow copies may be lost, starting with the oldest shadow copies.
If defragmenting volumes on which shadow copies are enabled, use a cluster (or allocation unit)
size of 16 KB or larger. Using this allocation unit size reduces the number of copy outs occurring
on the snapshot. Otherwise, the number of changes caused by the defragmentation process can
cause shadow copies to be deleted faster than expected. Note, however, that NTFS compression
is supported only if the cluster size is 4 KB or smaller.
NOTE: To check the cluster size of a volume, use the fsutil fsinfo ntfsinfo command.
To change the cluster size on a volume that contains data, back up the data on the volume, reformat
it using the new cluster size, and then restore the data.

Mounted drives

A mounted drive is a local volume attached to an empty folder (called a mount point) on an NTFS
volume. When enabling shadow copies on a volume that contains mounted drives, the mounted
drives are not included when shadow copies are taken. In addition, if a mounted drive is shared
and shadow copies are enabled on it, users cannot access the shadow copies if they traverse from
the host volume (where the mount point is stored) to the mounted drive.
For example, assume there is a folder F:\data\users, and the Users folder is a mount point
for G:\. If shadow copies are enabled on both F:\ and G:\, F:\data is shared as
\\server1\data, and G:\data\users is shared as \\server1\users. In this example,
users can access previous versions of \\server1\data and \\server1\users but not
\\server1\data\users.

Managing shadow copies

The vssadmin tool provides a command line capability to create, list, resize, and delete volume
shadow copies.
The system administrator can make shadow copies available to end users through a feature called
"Shadow Copies for Shared Folders." The administrator uses the Properties menu (see
Figure 34 (page
determine the frequency with which shadow copies are made.
If shadow copies are stored on the same volume as the user files, note that a burst
66)) to turn on the Shadow Copies feature, select the volumes to be copied, and
Volume shadow copies 65