What is the difference between obsolete and expired Backup in RMAN?
Obsolete Backup: Backup pieces or backup sets which are not needed for recovery.
We can use the REPORT OBSOLETE command to list the obsolete backups and DELETE OBSOLETE command to delete the obsolete backup.
Expired Backup:When the CROSSCHECK command is used to determine whether backups recorded in the repository still exist on disk or tape, if RMAN cannot locate the backups, then it updates their records in the RMAN repository to EXPIRED status.We can then use the DELETE EXPIRED command to remove records of expired backups from the RMAN repository.