If one or more specific backups are unavailable because of a temporary condition, such as a disk drive that is temporarily offline or a tape stored offsite, then you can mark those backups as unavailable. Oracle Recovery Manager (RMAN) does not use unavailable backups to restore or recover data.
Note:
Backups stored in the fast recovery area cannot be marked as unavailable.
RMAN keeps the record of unavailable backups in the RMAN repository and does not delete backups listed as unavailable when you delete expired backups. If the unavailable backups become accessible again, then you can mark them as available.
See Also:
Oracle Database Backup and Recovery Reference for the syntax used for multitenant container databases (CDBs) and pluggable databases (PDBs)
To mark backups as available or unavailable: