Archiving the Offline Redo Log Files 

Purpose

Oracle backs up the online redo log files for the database system in the archiving directory <ORACLE_HOME>/saparch , so creating the offline redo log files. If you need to recover your database you must have all offline redo log files that have been written since the recovery backup; otherwise you can only recover the database to the point in time before any missing redo log entry. You must always archive the offline redo log files after a database backup, and immediately after an online backup. In production systems, make two copies of the offline redo log files; in test systems one copy is enough.

The Oracle database will hang if the database is operated in ARCHIVELOG mode but the archiving process ARCH cannot save the online redo log files because the archiving directory is full. This situation is called Archiver Stuck. If this occurs you must shut down the database with shutdown abort ; the subsequent startup of the database takes a long time, since Oracle must perform an instance recovery. To avoid this, back up the offline redo log files regularly to tape. How often you do this depends on the amount of activity in your R/3 System. If a lot of redo log entries are written, and the redo log files are therefore switched frequently, you should constantly monitor the archiving directory and archive and delete the offline redo log files when necessary.

Prerequisites

You can archive the offline redo log files regardless of the current status of the database and the SAP System. If you have configured your system according to the SAP recommendations, the Oracle database system will save the online redo log files (where the changes made to the database are recorded) automatically (offline redo log files are written). If you have not changed the standard profile init<DBSID>.ora , the offline redo log files are located in the archive directory <ORACLE_HOME>/saparch (see Archiving Parameters).

You can also directly archive the offline redo log files by calling the right command option for BRARCHIVE. Read about the options in the SAP Backup Utilities, especially using BRBACKUP and BRARCHIVE. Make sure the necessary parameters have been set for BRARCHIVE in the the profile init<DBSID>.sap.

Procedure

  1. Select the SAPDBA option Backup archive logs to call the BRARCHIVE program. Based on the BRARCHIVE parameters configured in the init<DBSID>.sap profile, archiving is started with the following defaults:
  2. simple archiving

    all offline redo log files

    to a local tape device, tape size 1200 MB

    without file compression

  3. You can change these default values if necessary. SAPDBA only allows you to change some of the parameters in init<DBSID>.sap . If you have to make other changes, you will have to change the initialization profile manually and then restart SAPDBA.
  4. Start BRARCHIVE.

Result

Check the summary log ( arch<DBSID>.log ) to see which return code was sent when the archiving was completed. For information on the progress of the archiving, see the detail log ( a<encoded timestamp>.<ext> ).
See
BRARCHIVE Logs

Example

Sample Logs