Resolving The Problem

When the Oracle backup is performed the control file is included with one of the pieces that is backed up. This allows for several different scenarios to attempt to restore the control file. Since these scenarios can be quite complex, it is suggested that Oracle Support be contacted for assistance as a first step in the process.

1. The easiest means to restore the control file is when the RMAN Catalog exists and is viable for the restore. Look in the RMAN Catalog for the control file backup piece. Using the RMAN Catalog, Oracle support should be able to assist in restoring the control file.

2. If method one is not possible because there is no RMAN Catalog or it has been destroyed in addition to the control file not being available, then method two is the last resort, but not a guaranteed resolution.

Without an existing control file (and no RMAN catalog), there is no means to identify which backuppiece contains the control file.

If an autobackup of the control file was performed, then the restore of the control file can be accomplished by directly calling the autobackup process for the control file restore, for example:
RESTORE CONTROLFILE FROM AUTOBACKUP

If there is no RMAN catalog and the control file was not backed up using autobackup, then the trick is to try to locate the control file within the backuppieces from the last Oracle backup. Oracle technote ID 403883.1
How To Restore Controlfile From A Backupset Without A Catalog Or Autobackup
outlines how to proceed. The pieces needed to perform the restore, can be identified on the Tivoli Storage Manager server using the following select statement with the Tivoli Storage Manager Administrative client:

SELECT * FROM BACKUPS WHERE NODE_NAME='ORACLE_NODENAME'

The ORACLE_NODENAME must be uppercase and surrounded by single quotes.

There are additional details and considerations for this type of disaster recovery restore of the control file outlined in Oracle Technote 372996.1,
"RMAN Restore and Recover of a Database When the Repository and spfile/init.ora Files are Lost".
Using this technote, with the assistance of Oracle support, it should be possible to recreate the control file.