Block before backing up
Before you begin an external backup, block the database server. Blocking forces a checkpoint, flushes buffers to disk, and blocks user transactions that involve temporary tables.
During the blocking operation, users can access that database server
in read-only mode. Then you can physically back up or copy the data
to another set of disks or storage media by using operating-system
or third-party tools. When you complete the external backup, unblock
the database server so that transactions can resume. You should include
all the chunk files in each storage space, administrative files, such
as onconfig, and the emergency boot file, in
an external backup.
Important: To make tracking backups
easier, you should back up all storage spaces in each external backup.
ON-Bar treats an external backup as equivalent to a level-0 backup. You cannot perform an external backup and then use ON-Bar to perform a level-1 backup, or vice versa because ON-Bar does not have any record of the external backup. For more information, see Performing an external backup when chunks are not mirrored.