Why would you run the delete obsolete command? (Choose all that apply.)
A.
To remove missing backup set pieces physically from disk
B.
To remove metadata related to backup set pieces in the control file and the recovery catalog
C.
To mark as deleted records in the control file and the recovery catalog associated with obsolete backup sets
D.
To delete backup set pieces associated with backups that are no longer needed due to retention criteria
E.
To remove old versions of RMAN backups
Explanation:
Deleting Expired RMAN Backups and Copies
If you run CROSSCHECK, and if RMAN cannot locate the files, then it updates their records in the RMAN
repository to EXPIRED status. You can then use the DELETE EXPIRED command to remove records of
expired backups and copies from the RMAN repository.
The DELETE EXPIRED command issues warnings if any files marked as EXPIRED actually exist. In rare
cases, the repository can mark a file as EXPIRED even though it exists. For example, a directory containing a
file is corrupted at the time of the crosscheck, but is later repaired, or the media manager was not configured
properly and reported some backups as not existing when they really existed.
To delete expired repository records:
If you have not performed a crosscheck recently, then issue a CROSSCHECK command. For example, issue:
CROSSCHECK BACKUP;
Delete the expired backups. For example, issue:
DELETE EXPIRED BACKUP;
Deleting Obsolete RMAN Backups Based on Retention Policies
The RMAN DELETE command supports an OBSOLETE option, which deletes backups that are no longer
needed to satisfy specified recoverability requirements. You can delete files that are obsolete according to the
configured default retention policy, or another retention policy that you specify as an option to the DELETE
OBSOLETE command. As with other forms of the DELETE command, the files deleted are removed from
backup media, deleted from the recovery catalog, and marked as DELETED in the control file.
If you specify the DELETE OBSOLETE command with no arguments, then RMAN deletes all obsolete backups
defined by the configured retention policy. For example:
DELETE OBSOLETE;