Restore Failover
RMAN automatically uses restore failover to skip corrupted or inaccessible backups and look for usable backups. When a backup is not found, or contains corrupt data, RMAN automatically looks for another backup from which to restore the desired files.

RMAN generates messages that indicate the type of failover that it is performing. For example, when RMAN fails over to another backup of the same file, it generates a message similar to the following:

failover to piece handle=/u01/backup/db_1 tag=BACKUP_031009
If no usable copies are available, then RMAN searches for previous backups. The message generated is similar to the following example:

ORA-19624: operation failed, retry possible
ORA-19505: failed to identify file "/u01/backup/db_1"
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3
failover to previous backup
RMAN will perform restore failover repeatedly until it has exhausted all possible backups. If all of the backups are unusable or no backups exists, then RMAN attempts to re-create the datafile. Restore failover is also used when there are errors restoring archived redo logs during RECOVER, RECOVER ... BLOCK, and FLASHBACK DATABASE commands.