Split Mirror Disks Backup
If you want to make an offline or online backup of your database, whilst avoiding downtime, the ‘split mirror disks’ configuration is a recommended solution (especially for large databases). From SAP Release 4.0 this configuration is completely supported by the SAP backup tool BRBACKUP.
In the split mirror configuration disks of the primary host, on which the productive database runs, are mirrored. BRBACKUP runs on a secondary host, which carries out the database backup for this ‘backup host’ after the mirror disks have been split and mounted. This saves the primary (productive) host backup work and the performance of the SAP R/3 System is not affected.
The resynchronization of the ‘backup database’ with the productive database can be done after the backup using BRBACKUP. If you want to use the backup host as a ‘reporting server’ you can carry out the synchronization yourself at a later time.
BRBACKUP also communicates with the productive database. By doing this it receives information on the database structure and saves the results of the backup. This enables the CCMS (Computing Center Management System) of the productive R/3 System to monitor the backups.
The BACKINT interface is also supported in the split mirror configuration. This configuration is transparent for BACKINT and no additional aspects have to be taken into account.
The split mirror disks scenario only includes backups with BRBACKUP. BRARCHIVE backups are not included as they do not place any significant load on the productive host. As standard the backup of the offline redo log files is done on local or remote tape devices, on disk or with BACKINT.
If you want to carry out an offline backup the database must be shut down for a few minutes for the splitting of the disks.