BRBACKUP or BRARCHIVE automatically selects the volumes that are recommended for the next backup. The name of the mounted volume is compared to the name found in the volume pool. In addition, the procedure ensures that current backups are not overwritten.
Automatic Volume Management
When you use automatic volume management, do not use weekdays or days of the month in the volume names, because BRBACKUP or BRARCHIVE does not check whether or not a holiday fell in the period since the last backup. SAP recommends that you include the name of the database instance and a sequential number in the tape name, for example <DBSID>A<nn> for BRARCHIVE tapes, <DBSID>B<nn> for BRBACKUP tape volumes.
1. Define a pool of the volumes available for the backup. To do this, enter the corresponding volume names in profile parameter volume_backup or volume_archive. All the volumes defined there should physically exist. Initialize new volumes when necessary.
3. Start the backup with BRBACKUP or BRARCHIVE without option –v|-volume. Only volumes that are not locked are selected from the pool of available volumes.
4. Mount the requested volumes. During the next runs, BRBACKUP and BRARCHIVE attempt to write to all the available volumes in the pool in sequence.
5. You can display the names of the volumes required for the next run as follows:
6. You can check whether you have mounted the correct volume in the backup device with:
brbackup -q check
brarchive -q check
These commands do not actually start the backup. In particular, you can use these options before scheduling a backup with CRON or a similar tool.
For more information, see -q|-query.
If you want to select the volumes manually you can deactivate automatic tape management. To do this, set the init<DBSID>.sapparameters volume_backup and volume_archive to SCRATCH or call BRBACKUP or BRARCHIVE with the option -v SCRATCH. For more information, see Scratch Volume.