Snapshot Settings - HP StorageWorks 8000 - NAS Command Reference Manual

Snapshot Settings

34 Command Reference
A snapshot is a read-only picture of a file volume at a specific point in time. When you create a
file volume, the snapshot of that file volume is of zero length. However, as you modify the file
volume, the snapshot tracks changes between the original file volume and the modified file
volume. If an error occurs and you want to revert to the previous version, you can use the
snapshot data and the unmodified parts of the original file volume to quickly and easily
construct the file volume.
When you set up a snapshot, consider how quickly the file's data will change, and how often
you will delete snapshots and start over. You have the option to size snapshots relatively small
and let them autogrow. As they reach the limit that you establish, their size can increase by
approximately 10 percent to accommodate the changes. This flexibility lets you set the snapshot
and not worry about a specific size.
After you specify a size, you must define an expiration date. When the snapshot expires, the
system automatically deletes it. Consider your overall backup strategy in light of the snapshot
expiration date. For example, you may want to take a snapshot of your data for a specified
amount of time, then when you are certain that you have a backup of your system, delete the
snapshot and begin the snapshot process again.
The system treats snapshots as part of a regular file volume. The following commands are used
to create and manage snapshots.
getStorageVolumeFileVolumeSnapshotList
Returns a list of snapshots that exist for the specified file volume.
I inParam[0] = File volume name
I
outParam[0:N] = Snapshot name list
getStorageVolumeFileVolumeSnapshotCount
Returns a count of how many snapshots have been taken of the specified file volume.
I inParam[0] = File volume name
I outParam[0] = Snapshot count
getStorageVolumeSnapshotList
Returns a list of the snapshots that exist on the HP NAS 8000 system.
I outParam[0:N] = Snapshot name list
addStorageVolumeSnapshot
Creates a new snapshot of the specified file volume.
Note Adequate space must exist in the volume group that contains the file volume.
I
inParam[0] = Snapshot name
I inParam[1] = Volume name
I inParam[2] = Size (MB)