Consistent Online Backup

Definition

A consistent online backup of your Oracle database is an alternative to an offline backup when you cannot close the database. An online backup has logically consistent data because the offline redo log files created during a backup are backed up with the database files on the same backup volume. You use BRBACKUP for a consistent online backup.

A consistent online backup differs from an offline backup in that a recovery of the database – that is, applying the redo log files – is always necessary in order to guarantee consistent data.

Distinguish between the following, which are completely independent:

?      Backup of the offline redo log files using BRBACKUP during a consistent online backup, as described in this section

?      Backup of the offline redo log files using BRARCHIVE as a separate operation – for more information, see -a|-archive.

Use

Database recovery is simplified because the offline redo log files of the same backup can be applied. In the same way the database can be reset to an earlier status (Whole database reset).

We recommend consistent online backups, especially for monthly and yearly backups, when an offline backup is unacceptable. However, consistent online backups cannot replace backups of the offline redo log files with BRARCHIVE.

To perform a consistent online backup, use the BRBACKUP option -t|-type online_cons or the relevant init<DBSID>.sap profile parameter backup_type = online_cons.

To restore the offline redo log files from the BRBACKUP backups, use the BRRESTORE option -m|-mode archive_logs. Restore a complete BRBACKUP backup including offline redo log files using the BRRESTORE option -m full.