Monday, July 27, 2009

Extract Controlfile, Datafiles & Archivelogs from RMAN Backupsets

The other day, one of my colleagues posed me this interesting and thought-provoking question/scenario: "Suppose, you were to lose both your production and your RMAN catalog databases irrevertably. You do have a full/incremental RMAN backup, however. How are you going to recover?"

How indeed? I scratched my head and shone a torch upon the dark recesses of my memory to come up with an answer. The light (of the torch) did indeed reveal something - that is that a note existed in Metalink which list the method that could be used to delve into a RMAN backup set to extract the controlfile, the datafiles and also the archivelogs and Voilà, I hit the nail right on the head.

I did some more digging and found a bunch of "Notes" in Metalink that pointed me to the eventual answer to the above question. The Notes that I am referring to are listed below. A summary of the procedure to be followed in such scenarios is also provided. All the notes mentioned use the package dbms_backup_restore.


A successful production backup (RMAN) is available (cold or hot - if hot, then the archivelogs are also available) while the production and the RMAN catalog databases are irrevertably lost.


1. RMAN is being used to backup the database.

2. The RMAN backup is a "good" backup and is restore and recovery ready.

3. The list of datafiles (file name + full file path) and their datafile numbers is available (this can be obtained from the RMAN backup log file).

Solution Summary (from Note ID: 388057.1):

1. Start the target instance (nomount).

2. Restore the latest controlfile, ideally from the same backupset as the last incremental to be restored (Note 388052.1 : restore controlfile using PLSQL).

3. Make further copies if necessary as per the target database init.ora (pfile).

4. Mount the target instance (alter database mount).

NOTE: (RMAN may be able to be used to restore / recover the database at this point if the controlfile restored knows about the backup required to be restored and recovered).

5. Restore the datafiles from the level 0 backupset (Note 388053.1 : restore datafiles using PLSQL).

6. Restore (apply) the datafiles from the incremental backupsets (Note 388054.1 : restore incremental backups using PLSQL).

7. Restore the archivelogs from the archivelog backupset (Note 388055.1 : restore archivelogs using PLSQL).

8. Using traditional recovery techniques, recover the database using SQLPLUS. (until cancel using backup controlfile).

9. Open the database (resetlogs).

10. Rebuild the recovery catalog & re-register the target database.

11. Make backups of the target database and recovery catalog database.


1. 60545.1 - How to Extract Controlfiles, Datafiles, and Archived Logs from RMAN Backupsets

2. 388052.1 - How to Extract the Control file from an RMAN backupset using PL/SQL

3. 388053.1 - How to Extract Datafile(s) from an RMAN backupset Level-0(Full) backup using PL/SQL.

4. 388054.1 - How to Extract Incremental Backups of Datafile(s) from an RMAN Incremental backupset Level-1 or higher using PL/SQL.

5. 388055.1 - How to Extract archive logs from an RMAN using PL/SQL.

6. 388057.1 - How to Restore an RMAN Backed up database using PL/SQL.

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