Unless you have a great many database backups to manage, most DBAs using RMAN use the control file as a catalog instead of a catalog database. This simplifies management, but can make some types of recovery difficult. In a typical non-catalog RMAN recovery, the control file is restored and the instance is started for an RMAN restore and recovery. This method will provide a complete recovery to the point that the control file was backed up.

What happens, however, if that control file is lost? You can recover to the previous day’s backup (if you have it), but subsequent backups of the archive logs and then a full backup will be stored in a new control file backup. This is exactly what happened at a client of mine a few weeks ago. The backup script failed to back up the final archive log after the full backup. Due to Murphy’s Law, that was the exact backup that was needed to restore after a storage issue. Without the final archive log, the database threw the classic error:

ORA-01152: file 1 was not restored from a sufficiently old backup
ORA-01110: data file 1: ‘+DGROUP1/dmlive/datafile/system.294.689876999′

I had no previous copy of the control file except that of the night before, I did, however, have all of the archive logs in an RMAN backup set. But how to tell the control file that they exist? With a catalog database, all the backupsets already recorded, but the control file method is only as good as its last writing by RMAN. There is a method, however.

Using the previous nights control file, use RMAN to restore and recover all database and archivelogs. Do NOT try to open the database. Find the filename of the backupset that contains the archivelogs that are needed, and run the following command withing RMAN:

catalog backuppiece 
       '/backups/DMLIVE_9497_1_689621187_2009_Mon_full';

Once this is complete, restart the recovery using the same control file to roll forward through all the newly cataloged archive logs. Once complete, open the database with the resetlogs option and you are all set.

Happy recoveries!