HP StorageWorks 8000 - NAS User Manual page 141

6. Enter the maximum size for the snapshot volume in the Snapshot Capacity
field. A snapshot cannot exceed the file volume size.
7. In the Snapshot Capacity Policy box, select either:
— Auto Grow at and select a percentage from the drop-down list to allow
the snapshot to grow automatically if it is almost full. Allow a sufficiently
large margin in the autogrow configuration. If a snapshot becomes full,
the NAS 8000 has no place to write the old blocks from the logical
volume as they change, so the snapshot is no longer a true snapshot. It is
therefore invalidated and dropped. At this point, the Command View NAS
interface will not allow any further use/manipulation of the snapshot. The
only recourse is to delete the snapshot.
Note: Remember, after the snapshot has been taken, when a file changes,
the original file (at the time the snapshot is taken) is copied to the
snapshot volume. So, for every file that changes, snapshot capacity is
consumed. You want to specify a large enough capacity so that an original
copy of all files that change is saved, but not so large that the snapshot
volume takes up a lot of valuable storage space. You can always resize a
snapshot at a later time.
— Send Notification at and select a percentage from the drop-down list to
send an SNMP alert when the space used on a snapshot volume reaches a
certain percentage. When data is written to the new snapshot, the
available space in the snapshot volume decreases. Note: This percentage
is used in conjunction with the settings you entered on the SNMP alert,
email, and Syslog configuration pages.
8. In the Snapshot Scheduler, select either Once, Daily, Weekly, or Monthly
and specify the date and time information. When a snapshot is scheduled to
occur more than once, the date and time of the occurrence is appended to the
snapshot name that you specified. That way, older snapshots remain on the
volume and are not overwritten.
9. In the Snapshot Expiration Policy box, select one of the following:
— Never if you don't want this snapshot to be automatically deleted. If you
select this option, you must delete the snapshot manually.
— On This Date and specify a date and time for the snapshot to be deleted.
— After and specify a day, week, or month value.
10. Click OK to create the snapshot.
Managing Your Storage
141