Show TOC

Process documentationRecovery with DB2 for Linux, UNIX, and Windows Locate this document in the navigation structure

 

To minimize downtime with your DB2 for Linux, UNIX, and Windows database, you must make sure that you can quickly recover the database in the event of a failure with loss of production data. There are the following types of recovery with DB2 for Linux, UNIX, and Windows:

  • Crash recovery

    This is required if structures on disk are not damaged, but the database instance has aborted.

  • Media recovery

    This is required if structures on disk such as a container are damaged.

Process

  1. Devise a recovery strategy and rehearse it in practice.

    SAP strongly recommends you to rehearse a disaster. You could, for example, use a test system to practice restore and roll-forward.

    This exercise helps give you some idea how long a recovery takes in practice.

  2. Repeat the recovery rehearsal frequently enough (for example, twice a year) to allow for the effects of database growth on recovery time.

  3. Choose one of the following types of recovery to restore the DB2 for Linux, UNIX, and Windows:

    • Crash recovery

      In the case of a system crash and a subsequent database restart, DB2 for Linux, UNIX, and Windows automatically recovers the database. For this, the AUTORESTART database parameter is enabled by default in your SAP database.

      Note Note

      The database always creates log files during crash recovery. If there is not enough log space, the recovery fails.

      End of the note.

    • Restore recovery (media recovery)

      This type of recovery enables the restore of a previous version of the database that was made with the DB2 backup command.

    • Roll-forward recovery (media recovery)

      A roll-forward recovery follows the restore of the database by applying the transaction logs created since the last restored backup.

      Note Note

      You can perform roll-forward recovery if the database has been configured for LOGRETAIN=ON and LOGRETAIN=ON. This setting is mandatory for production SAP systems.

      End of the note.

  4. Use parallel recovery and parallel roll-forward.

    Consider using parallel recovery by using parameters parallelism and device of restore command. You can turn on parallel roll-forward by setting DB2_USE_PARALLEL_RECOVERY=YES using the db2set command.

Result

You can restore your database as quickly and efficiently as possible, so avoiding downtime caused by a failure with loss of database data.

More Information

IBM documentation Data Recovery and High Availability Guide and Reference, for example, for DB2 V9.7 for Linux, UNIX, and Windows, at:

http://www-01.ibm.com/support/docview.wss?rs=71&uid=swg27015148