Storix Software SBAdmin TSM Edition Users Guide - Manual (Page 52)

Storix System Backup Administrator 52 Version 8.2 TSM Edition User Guide
a. One at a time (sequentially). Select this option if a snapshot should be created individually when the
data in that logical volume (or filesystem) is to be backed up. When the backup of this LV completes,
the snapshot is removed (resyncd). This option is recommended if there is no relational data between
different logical volumes and filesystems that must be backed up at the same point-in-time.
Less disk space is required since only one snapshot LV is created at a time. For AIX 6.2 using internal
snapshots, no separate logical volume is created, so the added space does not apply. But, in any case,
when creating and removing snapshots one at a time, the snapshot exists for a lesser time, reducing
the amount of data written to it, thereby decreasing the possibility of running out of space in the
snapshot.
b. At the same time (concurrently). Select this option if a snapshot of all logical volumes to be included
in a backup should be created at the same time. This is important if there is relational data between
different logical volumes and filesystems that require that the data from all logical volumes be backed
up from the same point-in-time. For the reasons described above, this option is not recommended if
there is no relational data between different logical volumes.
4. If a snapshot cannot be created:
a. Use active filesystem. If this option is selected, then the failure to create a snapshot of the logical
volume or filesystem will result in the backup using the original (online) copy without a snapshot. The
result would be the same as if snapshot backups were not configured for this logical volume or
filesystem.
b. Abort the backup. Select this option if the client backup should abort when a snapshot cannot be
created.
If
concurrent snapshot backup is performed, all snapshots will be removed and the backup of the
client will terminate, but the job will continue processing other client backups, if any.
If
sequential snapshot backups are performed, no snapshots will exist at this point, but there may have
already been some data written to the backup media. Therefore, both the backup and job will
terminate, preventing other backups from continuing to write to the backup media.
Possible issues preventing a logical volume or filesystem snapshot from being created include:
1 ) A snapshot LV already exists for the logical volume. Another snapshot backup may not have removed
the snapshot due to a program failure, or another (non-SBAdmin) process may have created a
snapshot LV.
2 ) There may not be enough space in the volume group to create the snapshot logical volume. If this is
the case, you need to expand the volume group, remove other unused logical volumes, or select to
create smaller snapshots using the
Size (%) option.
When all selections have been made, press the Save button. The settings for the selected client will be saved
and you may then select a different client for which to configure snapshot backups.
If you wish to remove prior settings for a client, select the Remove Settings button. If selected, the prior
configuration will be removed and no backups performed on that client will use snapshot backups, even if the
backup job configuration indicates that snapshots should be used.