RMAN catalog backup: One catalog vs. multiple catalogs

Database Backup and Recovery expert Brian Peasland explains why the best approach is to have one Recovery Catalog for all databases.

We are using a central database to host RMAN repositories and the catalogs are separated based on version and function, i.e. RMAN817_DEV, RMAN920_QA, RMAN102_PROD, etc. This totals to more than 15 catalogs.

There is a difference of opinion on what is a "better" approach -- having multiple separated catalogs or having a fewer number of catalogs, maybe separated just by function or the version. Both sides are using the same reasons for cons and pros, and I'd like to hear your opinion and reasons for doing this one way versus the other.

Personally, I would lean towards the side of having one recovery catalog (RC) for all databases. One RC can handle hundreds of databases without problems. I'm not sure why I would have more than one RC for all of these databases.

That being said, the only time I have implemented two RCs is to have a RC of my main backup RC. For instance, all of my databases use a RC in a database called RMAN_RC. Every time I use RMAN to back up a database, it connects to the RC in the RMAN_RC database. But I cannot use this RC when backing up the RMAN_RC database itself. So I will sometimes create another RC in another database. This way, if I lose one RC, the information to restore it is in another RC. I hope that makes sense.

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