Two-Phase Backup 
As an alternative to a direct backup to tape you can make a two-phase backup with the complete support of BRBACKUP. This backup strategy enables you to easily make a disk backup, as well as having several copies of this and previous backups available. For a recovery, SAPDBA can, in this case, access the disk backup directly. If a backup from tape is required then the files are directly copied to the original directories by BRRESTORE.
You can also carry out the second phase of the two-phase backup with external means (backup programs, operating system utilities, and so on). The user then has full responsibility for the complete and correct execution of this phase.
Backups to raw devices cannot be backed up to tape in a second phase with the BACKINT interface. In this case save directly to tape.
BRBACKUP: Two-Phase Backup
Phase 1
BRBACKUP backup to disk.
Phase 2
BRBACKUP backup from disk to tape
Restore phase:
BRESTORE restoration from tape directly to the original directories or BRRESTORE from the disk to the original directories.
To make the backup to tape (phase 2) start BRBACKUP with the relevant command option (see
-b|-backup).
Advantages
The first phase can be much shorter than a direct backup to tapes.
In the case of a recovery the restoration phase is shortened, if the backup is directly available on the disk.
When restoring from tape, BBRESTORE can write the backed up files directly to the original directories.
Volume management and all other automatic actions of BRBRACKUP can be fully utilized in the second phase.
Disadvantages
The hardware requirements (disk storage and storage tapes) must be fulfilled. Additional disk storage space is required, in comparison to a direct backup to tape.
BRBACKUP has to be started twice for a two-phase backup.
The backup type (offline, online) and the extent of the backup (full, partial) must be identical in the first and second phases. In an offline backup the database remains open in the second phase.
BRARCHIVE: Two-Phase Backup
Two-phase backup of the offline redo log files using BRARCHIVE runs analog to the BRBACKUP backup. You cannot, however, make any number of copies to tape (maximum of two). We thoroughly recommend a backup of the offline redo log files to tape, in addition to a disk backup.
- Phase 1
BRARCHIVE backup to disk
- Phase 2
BRARCHIVE backup from disk to tape
- Restore phase:
BRRESTORE restoration from tape directly into the original directories or direct import of offline redo log files in an SAPDBA recovery from disk (no restoration).
To make the BRARCHIVE backup of the offline redo log files to a volume start BRARCHIVE with the appropriate command option (see
-a|-archive).
Advantages
The first phase can be much shorter than direct backup to the volume, therefore the SAPARCH directory is emptied more quickly.
In a recovery situation, the restoration phase can be much shorter, if the backup of the offline redo log files is directly available on disk. In this case SAPDBA uses the offline redo log files directly from the disk. There is no restoration.
When restoring from tape BBRESTORE can write the backed up offline redo log files directly to the SAPARCH directories.
The volume management of BRARCHIVE can be fully utilized in the second phase of the backup.
Disadvantages
A maximum of two copies of the offline redo log files can be backed up to tape, regardless of the way in which the offline redo log files are backed up: directly to tape or with a disk backup.
Additional storage space and storage tapes are required.
BRARCHIVE must be started twice for a two-phase backup.