Recovery window for tape backups

Question

Hope someone can answer to my questions.
With RMAN you can maintain the number of tape backups that are needed for recovery purpose through the “delete obsolete recovery window” command. E.g. the command below ensures tape backups be kept for recovery within 31 days:
delete noprompt obsolete recovery window of 31 days device type 'SBT_TAPE';
Q:
1)     If I use a disk area as pseudo tape area in my backups (through ORACLE.DISKSBT library parameter), I guess the above "delete noprompt obsolete recovery window" command would work on the pseudo tape area as well?
2)     At my site the pseudo tape area is backed up to tape nightly through the system backup job, and the tape backups are kept for about 1 month by the tape system. To save space in the pseudo tape area on disk can I just set a small recovery window in the above DELETE command (say 1 day) , and relies on the actual tape system retention policy for oracle backups? How would this affect oracle’s ability to do recovery?
Thanks

Answer 1

1) I would never use a 'faked' tape as a permanent solution - only to test tape backup scripts - , as it slows down the backup/recovery process. From RMAN's point of view a pseudo tape works like a real tape, so all valid commands apply.
2) When you delete a backup, RMAN forgets it. RMAN is not aware of still available backups in the tape system, you have to recatalog the backups. That means overhead in manual maintenance and a source for possible errors.
Werner