This TechNote recommends that you rather use RMAN to expire images:
http://seer.entsupport.symantec.com/docs/286221.htm
DOCUMENTATION: Best Practice for maintaining a consistent backup catalog between Oracle RMAN and NetBackup.
Extract:
A better approach to manage the catalog synchronization is to use the Oracle and Symantec recommended method. This method is to set the backup retention as an RMAN attribute, rather than a NetBackup attribute, and having RMAN delete obsolete, but unexpired, backups from NetBackup. The procedures to do this are documented in the Oracle Recovery Manager Guides for Oracle versions nine and later (
http://www.oracle.com/technology/documentation/index.html ). An outline of those procedures is shown below, but refer to the NetBackup and Oracle documentation for a complete description.
1. Set the NetBackup backup retention for Oracle backups to be either infinite or significantly longer than the RMAN retention.
2. Set RMAN retention for the number or duration to keep the backup sets in the RMAN catalog. If there is no RMAN catalog then use SQL to set an appropriate value for "control_file_record_keep_time". The minimum appropriate time would be the catalog backup retention time plus the maximum time between catalog maintenance operations.
3. On a regular basis, run the RMAN "delete obsolete" command to expire obsolete images from both the RMAN catalog and control file and from NetBackup.
4. If a "crosscheck" of the catalog is required, perform the "crosscheck" after obsolete backups are deleted by RMAN.
5. Stagger the initiation of RMAN catalog maintenance functions of any kind to limit the number of concurrent checks or deletion requests of the NetBackup master server by RMAN.
6. Perform the RMAN catalog maintenance functions on a more frequent basis to limit the number catalog requests of the NetBackup master server in a single session.
7. Ensure that the format specified for all RMAN backup piece names, except for autobackups of the control file, ends with a _%t as documented in the NetBackup for Oracle manual.
8. Avoid the creation of many small backup pieces of database files or archive logs.
Sample RMAN commands:
Please see the Oracle documentation (
http://www.oracle.com/technology/documentation/index.html ) for usage and explanation. These commands are not meant to be a step by step procedure; these are examples of the types of commands that are relevant to setting retention in RMAN and subsequent catalog maintenance.
SQL> show parameter control_file_record_keep_time;
SQL> alter system control_file_record_keep_time=90 scope=both;
RMAN> show all;
RMAN> configure retention policy to recovery window of 60 days;
RMAN> list backupset of database;
RMAN> list backupset of archivelog all;
RMAN> list backupset of controlfile;
RMAN> report obsolete;
RMAN> report obsolete orphan;
RMAN> allocate channel for maintenance type 'sbt_tape';
RMAN> delete obsolete;
RMAN> delete obsolete orphan;
RMAN> crosscheck backupset of database;
RMAN> crosscheck backupset of controlfile;
RMAN> crosscheck backupset of archivelog all;
A backup can be exempted from the retention policy with the backup or change command using the "keep" option. Be sure that these backups also use a NetBackup policy and schedule with the appropriate retention period.
RMAN> backup database keep forever logs;
RMAN> change backup of database <recordspec> keep until time 'sysdate+365' logs;
