Managing expired backup images
NetBackup and Oracle each maintain a repository of RMAN-initiated backup image information. The retention setting in the Application Backup schedule for RMAN stream-based backups determines the NetBackup image retention. But for RMAN proxy backups and OIP backups, the retention setting on the Automatic Backup schedule determines retention of the NetBackup image.
To manage expired backup images from the NetBackup repository, access the Retention setting of the Application backup schedule. Specify the length of time before NetBackup expires a backup image.
You can also manage the expired backup images from the Oracle repository. This method sets the backup retention as an RMAN attribute, rather than a NetBackup attribute. RMAN deletes the obsolete but not the unexpired backups from NetBackup. The following items are also part of this process:
Set the NetBackup backup retention for Oracle backups to be either infinite or significantly longer than the RMAN retention.
Set the RMAN retention to the number or duration to keep the backup sets in the RMAN catalog. If no RMAN catalog exists, then use SQL to set an appropriate value for "control_file_record_keep_time". The minimum appropriate time is the catalog backup retention time plus the maximum time between catalog maintenance operations.
On a regular basis, run the RMAN delete obsolete command to expire obsolete images from the RMAN catalog, the control file, and from NetBackup.
If a cross-check of the catalog is required, perform the cross-check after RAMN deletes the obsolete backups.
Stagger the initiation of RMAN catalog maintenance functions. Staggering is done to limit the number of concurrent checks or deletion requests that RMAN makes of the NetBackup master server.
Perform the RMAN catalog maintenance functions on a more frequent basis to limit the number of NetBackup catalog requests in a single session.
Ensure that the format that is specified for all RMAN backup piece names (except for autobackups of the control file) ends with
_%t.Ensure that the format that is specified for all RMAN backup piece names does not contain any space characters.
Avoid the creation of excessive, small backup pieces of database files or archive logs.
You can manually remove references to backup images from the Oracle RMAN repository. Use RMAN repository maintenance commands to remove references to backup files. You can use these commands to delete backup image information from both the Oracle RMAN repository and the NetBackup repository.
More information is available on the RMAN repository maintenance commands.
When a request is issued to delete a backup file from the RMAN repository, RMAN sends the request to NetBackup. The request tells NetBackup to delete the corresponding image from the NetBackup repository, regardless of the retention level.