Backup of Oracle instance Using RMAN Oracle Database Tips by Donald Burleson

Oracle Data Guard - Recovery Manager and Data Guard

Backup of a Oracle instance Using RMAN

This section will present the steps required to create a backup of the physical standby database. When backing up the standby database, it should be treated as the primary database and connections to it should be made using RMAN as the target database. Ideally, connect to the recovery catalog, as well, during the backup operation.

In the case where the recovery catalog cannot be used during the backup operation, use the standby control file as the repository.  In this case, the recovery catalog should be refreshed as soon as possible. If the recovery catalog is not updated with the backup information, that backup set cannot be used to recover the primary database.

Either a consistent or inconsistent backup of the Oracle instance can be created. If an inconsistent backup for recovery is used, a media recovery will certainly have to be completed. As a result, it is advisable to do a consistent backup of the Oracle instance to avoid any complication during recovery.

To create a consistent backup, shutdown the standby database, start it and mount it as a standby database. Do not start the managed recovery process or open it for read-only queries. Doing so will result in an inconsistent backup. Once the Oracle instance is mounted, execute the following two steps to create a backup set containing all the data files and archived redo log files:

• Set the ORACLE_SID to the standby dbsid and connect using RMAN as target:

DBA@jrbk01 export ORACLE_SID=stdbydb
DBA@jrbk01 rman target /

• This will not use the recovery catalog as the repository.
   

• Execute the following script to create a backup set in the /oracle/stdbydb/bkp directory. This script will need to be modified to suit the environment:

# Script: Create backup of standby database

Backup of a Oracle instance Using RMAN

run {
    allocate channel fs1 type disk
format='/oracle/stdbydb/bkp/%u.%p';
    backup
         incremental level = 0
         filesperset = 3
         database plus archivelog
         tag = 'level0Backup_OfStandby';
}

• The script will complete with the following warning:

"RMAN-06497: WARNING: controlfile is not current, controlfile autobackup skipped released channel: fs1"

• This warning shows up because the control file is a standby control file. This warning can be ignored because a backup of the standby control file is not usable in any sense for recovery.

To learn more about the backup of a standby database using RMAN, refer to Oracle 9i Recovery Manager User's Guide Release 2 (9.2), which provides a great deal of information on this subject.

Conclusion

The primary focus of this chapter was to introduce the concept of using Recovery Manager for physical standby database creation. The following topics were discussed in detail:

• Key Recovery Manager concepts and the explanation of RMAN terminology used throughout this chapter have been provided.
   

• Details on creating a physical Oracle instance using a backup set or image copies of the primary database were included.
   

• A step-by-step guide and a few sample scripts have been provided to assist when creating a physical Oracle instance using RMAN.
   

• The backup procedure for standby databases using RMAN was detailed.

Refer to Oracle 9i Recovery Manager User's Guide Release 2 (9.2), which provides much more additional information on this subject.