Let me suggest that you create a separate database dedicated to RMAN and its catalog. It may be on the same machine that you have your OEM database now. After you have created your RMAN catalog, you will need to register all the DB that you want RMAN to backup with it i.e RMAN database. When you create a new database, Oracle assigns a unique DBID to the database. This unique ID is what RMAN uses to distiguish between the databases that it backs up.
A word of caution here, you cannot copy a database from another and hope RMAN will back it up because of the DBID. Also, make sure that the RMAN database is at least 816. If your rman db is 815 and all your db are 816 you may run into problem.
Thanks for your prompt reply.
both my databases will be 8.1.6.
So are you trying to tell me that if i were to clone a database, it would have the same dbid as the database it was cloned from ?
I take it that I can clone a database and then register it and it would be thought of as a completely different database to the original even though both databases will be in the catalogue. Please confirm.
Also I am looking for the script which creates the rman catalogue.
I thought it was called ORACLE_HOME/rdbms/admin/catrman.sql, but there is no script named that here. Is it called something different in 8.1.6.
You cannot clone a database and hope rman will back it up. It will be better to create a new database register it with RMAN. Do export and import to get your new database populated and you will be set to go.