Pages

Friday, May 20, 2011

RMAN Configuration in Data Guard [Archivelog Deletion Policy]

Follow these steps to configure RMAN backups in Data Guard environment. When you want to managed the archivelog deletion policy from one centralpoint.

CONFIGURE ARCHIVELOG DELETION POLICY

Possible options :

APPLIED ON STANDBY - enables flash recovery area to delete archivelogs that are applied on mandatory standby.

NONE - enables flash recovery area to delete archivelogs that are backed up to tertiary device and that are obsolete based on the configured backup retention policy. This is the default configuration.

CLEAR - clears the deletion policy and returns the specified configuration to default value. The default value is NONE.


Viewing the Current Deletion Policy

To view the current setting (APPLIED ON STANDBY, CLEAR, NONE) for a database, issue the following query :
SELECT NAME, VALUE FROM V$RMAN_CONFIGURATION WHERE
NAME LIKE '%ARCHIVELOG DELETION POLICY%';

NAME VALUE
----------------------------- --------------
ARCHIVELOG DELETION POLICY TO APPLIED ON STANDBY


You can also find the existing configuration using the RMAN SHOW ARCHIVELOG

DELETION POLICY command:
RMAN> SHOW ARCHIVELOG DELETION POLICY
RMAN configuration parameters are:
CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON STANDBY;

When Backup is taken form the Standby Database.

Issue the following command on the primary database:
RMAN> CONFIGURE ARCHIVELOG DELETION POLICY TO NONE;
The following commands should be issued, after connecting to each of the other standby database servers.
RMAN> CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON STANDBY;
Reconfiguring the Deletion Policy After a Role Transition

By setting this configuration on each of the other standby databases (where backups are not being taken), it will enable automatic deletion of archived logs on this standby database that have been applied to all other remote standby destinations. By default, this configuration requires that at least one remote destination is set to mandatory. Archived logs are deleted if space in the Flash Recovery Area needs to be reclaimed for new files.

Note: Mandatory standby destination can impact the primary database if the standby destination cannot be reached.

Configure RMAN standby database where backups are taken:

Issue the following command on the physical standby where the backup will be taken.
RMAN> CONFIGURE DELETION POLICY TO NONE;
Specify when the archived logs can be deleted with the CONFIGURE ARCHIVELOG DELETION POLICY COMMAND. Since the logs are backed up at the standby site, you should specified the NONE option for the log deletion policy. This will enable automatic deletion of archived logs on the standby database that are outside of the retention period or that are already backed up to tape, if additional space is needed for new backups or archived logs.

On all the other physical standby databases where backups are note taken and the primary database.
RMAN> CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON STANDBY;
Note: That in the event of a switchover or failover, the database role changes and the appropriate CONFIGURE commands must be re-executed on new primary and standby databases.

More Information: