RE: rman configuration

That's mostly correct, just backwards on one point - it's to sync the catalog from the controlfile (the authoritative source), not the other way around. But you are correct that it's just a temp file not needed for restore/recovery operations, so to the OP - no need to change it. In fact, I don't think you can change it to tape. Maybe you're confusing the snapshot controlfile with controlfile autobackup? They are two completely different things and your controlfile autobackup goes to two places:  

1. On disk to $ORACLE_HOME/dbs (by default) whenver you make a change to your database structure (add datafile, tablespace, logfile, etc.)
2. To the same channel type as an rman backup, i.e. if you run a database or log backup to sbt_tape and have controlfile autobackup ON, then it will automatically run a controlfile autobackup to sbt_tape after the completion of the database/log backup.

Regards,
Brandon

Privileged/Confidential Information may be contained in this message or attachments hereto. Please advise immediately if you or your employer do not consent to Internet email for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of this company shall be understood as neither given nor endorsed by it.

--
http://www.freelists.org/webpage/oracle-l