Using backup optimization

Using this feature, the backup of files; that is, the data files, archived redo logs, and the backup sets which are already backed up to a destination device type will be skipped. Such optimization is very helpful to speed up the backups and reduce the size of the backup sets, especially for read-only tablespaces. Though this is something that should work with the normal BACKUP command, it doesn't! This option works only for the following commands:

• DATABASE

• ARCHIVELOG ALL/LIKE

• BACKUPSET ALL

• RECOVERY AREA

• RECOVERY FILES

• DATAFILECOPY

To see whether or not you have the backup optimization option on, you can use the SHOW command as follows:

RMAN> SHOW BACKUP OPTIMIZATION;

RMAN configuration parameters for database with db_unique_name ORCL12 are:
CONFIGURE BACKUP OPTIMIZATION OFF;

Since this is the default setting, let's take the backup of the archived logs and see whether they all come under the backup or not:

RMAN> BACKUP ARCHIVELOG ALL;

Since we have taken...