I need to restore an Oracle 220.127.116.11 database from Netbackup on to a different host. Is it possible to duplicate the DB with RMAN into an Auxiliary DB but without a recovery catalog? If it’s not possible directly can I restore backup pieces to disk first and then duplicate? What would be the procedure? Many thanks.
Yes, that's perfectly possible.
The main benefit of a Recovery Catalog is when restoring / recovering a database in place.
All the information needed to do the recovery is mastered in the Control Files so if you recover a database "over" itself, then the information needed to do that recovery is also overwritten. You get "one go" at doing the recovery and that's it.
So, if the Users look at the recovered data and say ...
Oh dear. Can we go back another hour?
... then the answer is, very simply:
A Recovery Catalog duplicates the information from the Control files, so you can have as many "goes" at an "in-place" recovery as you like.
When duplicating the database onto a new machine, there is no "overwriting" issue so yes, you can do this and, as long as you're prepared to trash the database and its files in between attempts, you can do so as often as you like.