Raw Devices with BRBACKUP and BRRESTORE

BRARCHIVE remains unchanged in a raw device configuration because offline redo log files must always reside in a file system.

There are some changes in the BRBACKUP and BRRESTORE programs in a raw device configuration, but these changes have no effect on the functional scope of the programs. The known functionality of BRBACKUP and BRRESTORE for backing up and restoring file systems remains unchanged.

BRBACKUP and BRRESTORE use the ddcommand to access raw devices:

·        With dd, you can write directly from the raw device to tape or to the raw device from tape (that is, backup to tape or restore from tape) and you can do the same to or from disk.

·        For a backup with software compression, dd output is sent directly to the compress. For a restore with decompression, output of uncompress is sent to dd.

·        For a backup on a remote computer, dd output is sent, for example, directly to rsh ( /remsh and so on). For a restore from a remote computer, it is sent from rsh ( /remsh and so on) to the dd command.

·        You can define options for ddcommand using the init<DBSID>.sap parameters dd_flags and dd_in_flags.

Since the dd command does not support a dd continuation tape (in this case an I/O error is reported), a method which is similar to the cpio continuation method is not supported. This means that each individual database file residing on the raw devices must completely fit onto one tape. This restriction does not refer to the BRBACKUP continuation tape management, which means that the BRBACKUP utility can request continuation tapes if they are necessary for backup of the next database files.