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Backup Optimization
Decrease backup time by skipping files for these operations
- BACKUP DATABASE
- BACKUP ARCHIVELOG ALL | LIKE
- BACKUP BACKUPSET ALL
Must turn optimization on
Effected by retention policy
Notes:
If you configure backup optimization on (the default is off), RMAN will skip datafiles, archive logs or backup sets under certain situations. For example, if the DBID and SCN of a datafile match the DBID and SCN of a backup of a datafile, and the datafile is offline, RMAN “might” skip it (i.e. omit it from the backup). I say that it might skip it because it also takes into account the configured retention policy. For example, if your retention policy is redundancy 2, RMAN skips the datafile only if 3 backups already exist. There are many factors involved in backup optimization. Refer to Chapter 5 of the Oracle9i Recovery Manager User’s Guide for complete details.
Note that backup optimization can be overridden with the FORCE parameter of the BACKUP command.