Compaq N2400 - TaskSmart - 1 GB RAM Administration Manual page 48

Snapshot Access
Snapshots can be read-write, and if they are shared, users can access a
snapshot and edit the data. If snapshots are shared with write access
enabled, it is recommended that a snapshot of the original snapshot be
created. There is no backup of the original snapshot unless a snapshot of
it is taken. By controlling the share permissions, administrators can
make snapshots read-only as an alternative to creating snapshots of
snapshots.
NOTE: Snapshots of snapshots can impede performance when both snapshots are
running on the same virtual disk.
The parent-child relationship of snapshots of snapshots is not
maintained on the server. Appropriate snapshot naming and volume
naming must be used to identify each snapshot individually. For
example:
G
Name the parent "Snapshot A"
G
Name the child "Child of Snapshot A"
Snapshots and Backup
Because snapshots are quick to create, it is possible to capture a coherent view
of the virtual disk data with little or no application downtime. Lack of
application downtime removes the traditional backup window or the amount of
time taken to back up to offline media. While many applications must be shut
down to capture an accurate backup, snapshots capture a point-in-time view of
the data that can be used as the source of backup data. Applications can
continue processing against the virtual disk data. Therefore, applications may
only have to be interrupted for a few seconds during the snapshot process.
CAUTION: Snapshots are not a replacement for reliable, periodic data backup.
If free pool space becomes critical, snapshots can be automatically deleted. See
"SWVR Lifeguard Service" later in this chapter. Also, snapshots are a short-term
convenience and reside on the same physical drives as the data. If something
happens to the data drives, the snapshots are also affected. Read Appendix A,
"Backup Utility Management," for suggestions on how to back up your
TaskSmart N2400 appliance.
Administrative Procedures 2-19