Backup of the Offline Redo Log Files with SAPDBA (SAP Library - SAP Database Guide: Oracle (BC-DB-ORA-DBA))

Backup of the Offline Redo Log Files with SAPDBA

Use

You can back up the offline redo log files with SAPDBA for Oracle. For more information about backup, see Backup, Restore, and Recovery. Oracle copies the online redo log files to the archiving directory, so creating the offline redo log files. You typically use SAPDBA for a one-off backup of the offline redo log files.

Recommendation

For routine backups, we recommend one of the following:

DBA Planning Calendar to schedule a backup and then view its log

A scheduler offered by a supplier of the BACKINT interface

The scheduler cron for UNIX or at for Windows

Like SAPDBA, these tools call the SAP tool BRARCHIVE to perform the backup.

Caution

If you need to recover your database you must have access to all offline redo log files that have been written since the database backup. Otherwise you can only recover the database to the point in time of the last available redo log. Therefore, you must always archive the offline redo log files after a database backup, and immediately after an online backup.

In production systems, we strongly recommend you to:

Run the database in ARCHIVELOG mode with automatic archival turned on. For more information, see Setting Up Archiving.

Make two copies of the offline redo log files. In test systems, one copy is often sufficient.

Integration

The Oracle database hangs if it is operated in ARCHIVELOG mode, but the archiving process cannot save the online redo log files because the archiving directory is full. This situation is called "archiver stuck." If this occurs you must back up the offline redo log files and delete them from the archiving directory as soon as possible.

To avoid archiver stuck, back up the offline redo log files regularly to tape. How often you do this depends on the amount of activity in your SAP System. If a lot of redo log entries are written, and the redo log files are frequently switched, be sure to constantly monitor the archiving directory. When necessary, archive and delete the offline redo log files.

For more information about avoiding "archiver stuck," see SAP Note 316642.

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 saves the online redo log files automatically as offline redo log files. Unless you have changed the standard profile init<DBSID>.ora, the offline redo log files are stored in the archive directory <SAPDATA_HOME>/saparch. For more information, see Setting Up Archiving.

You can also directly archive the offline redo log files by calling the correct command option for BRARCHIVE.

Make sure the necessary parameters have been set for BRARCHIVE in the Initialization Profile init<DBSID>.sap.

Activities

You call the function to back up offline redo logs in SAPDBA and check the displayed backup parameters, changing them as required.

The default values for the backup parameters, which are set in the initialization profile init<DBSID>.sap, trigger a simple archive of all offline redo log files to a local tape device without file compression.

Note

SAPDBA only lets you change certain parameters for the backup. If you have to make other changes, you must change the init<DBSID>.sap profile manually and then restart SAPDBA.

If required, you change the default values for the backup parameters in the initialization profile init<DBSID>.sap and restart SAPDBA.

You start the backup of the offline redo log files.

You check the results of the backup in the BRARCHIVE logs:

To check the archive return code, see the summary log, arch<DBSID>.log.

To check the progress of the backup, see the detail log, a<encoded timestamp>.<ext>.

For more information, see Backing Up the Offline Redo Log Files with SAPDBA.