Physical Standby Database Creation with RMAN

You can use the RMAN DUPLICATE command to create a physical standby database. (Note that RMAN cannot be used to create a logical standby database, because it is not a block-for-block duplicate of the primary database.)

RMAN automates the following steps of the creation procedure:

1. Restores the standby control file.

2. Restores the primary datafile backups.

3. Optionally, RMAN recovers the standby database (after the control file has been mounted) up to the specified time or to the latest archived redo log generated.

4. RMAN leaves the database mounted so that the user can activate it, place it in manual or managed recovery mode, or open it in read-only mode.

RMAN cannot fully automate creation of the standby database because you must manually create an initialization parameter file for the standby database, start the standby instance without mounting the control file, and perform any Oracle Net setup required before performing the creation of the standby. Also, you must have RMAN backups of all datafiles available and a control file backup that is usable as a standby control file, and those backups must be accessible by the standby instance under the same name.

Once the standby database is created, RMAN can be used to back up the datafiles, control file and archived redo logs of the standby. Backups of datafiles and archived redo logs taken from a physical standby database are fully interchangeable with primary backups. In other words, you can restore a backup of a physical standby datafile to the primary database, and you can restore a backup of a primary datafile to the physical standby database. The standby control file backups can be used to restore the standby control file without needing to re-instantiate the standby in cases where the standby control file is lost.