Log backups

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Archived logs for databases contain committed transaction data. This transaction data can be used to run a rollforward data recovery when you are running a restore operation. Using archive log backups enhances the recovery point objective for your data.

Ensure that you select the Enable Log Backups option to allow rollforward recovery when you set up a backup job or service level agreement (SLA) policy. When selected for the first time, you must run a backup job for the SLA policy to activate log archiving to IBM Storage® Protect Plus on the database. This backup creates a separate volume on the vSnap repository, which is mounted persistently on the Db2® application server. The backup process updates either LOGARCHMETH1 or LOGARCHMETH2 parameters to point to that volume for log archiving purposes. The volume is kept mounted on the Db2 application server unless the Enable Log Backup option is cleared and a new backup job is run.

Restriction: In Db2 multi-partitioned environments, the LOGARCHMETH parameters across partitions must match.

When either LOGARCHMETH1 or LOGARCHMETH2 parameters are set with a value other than OFF, you can use archived logs for rollforward recovery. You can cancel log backup jobs at any time by clearing the Enable Log Backups option: go to Manage Protection > Databases > Db2, select the instance and click Select Options. This change takes effect after the next successful backup job completes, and the LOGARCHMETH parameter value is changed back to its original setting.

Important: IBM Storage Protect Plus can enable log backup jobs only when the LOGARCHMETH1 parameter is set to LOGRETAIN or if one of the LOGARCHMETH parameters is set to OFF.

If the LOGARCHMETH1 parameter is set to LOGRETAIN.: IBM Storage Protect Plus changes the LOGARCHMETH1 parameter value to enable log backups.

If either LOGARCHMETH1 or LOGARCHMETH2 parameters are set to OFF and the other is set to DISK, TSM, or VENDOR.: IBM Storage Protect Plus uses the LOGARCHMETH parameter that is set to off to enable log backups.

If both LOGARCHMETH parameters are set to DISK, TSM, or VENDOR.: This setting combination causes an error when IBM Storage Protect Plus attempts to enable log backups. To resolve the error, set one of the parameters to OFF, and run the backup job with the Enable Log Backups option selected.

Truncating archive log backups

IBM Storage Protect Plus automatically deletes older transactional logs after a successful database backup. This action ensures that the capacity of the log archive volume is not compromised by retention of older log files. These truncated log files are stored in the vSnap repository until the corresponding backup expires and is deleted. The retention of database backups is defined in the SLA policy that you select. For more information about SLA policies, see Defining a service level agreement backup job.

IBM Storage Protect Plus does not manage the retention of other archived log locations.

For more information about Db2 settings, see IBM Db2 documentation.