User Guide

SAP AG November 2002
Backup ID
The database system automatically gives each backup a backup ID to allow them to be
identified. This ID uniquely identifies the backups done since the creation of the database
instance
.
If external backup tools are used for the backup, the backup is given an external
backup ID [Page 137].
The backup ID consists of the type of backup (complete or incremental
or ) and a sequential number.
data backup [Page
]131 log backup [Page 142]
Full and incremental data backups are numbered sequentially together. Log backups are
numbered in a separate sequence.
After the backup, the backup ID is written to the log dbm.knl. You can display all the
contents of this file in the backup history [Page
126].
In a restore, the ID is shown first and must be confirmed before the operation can start.
If the backup medium is a tape or a cassette, you should write the backup ID on
the sticker of the tape or cassette at the end of the backup.
Formal Description of the Backup IDs
<backup_id> ::= <save_type>_<sequence_no>
<save_type> ::= DAT | PAG | LOG
<sequence_no> ::= <number>
Backup Medium
A backup medium is assigned to every backup you carry out. Backup media include files,
tapes, autoloaders, and pipes.
Backup media can be defined before or during the backup process and they are defined
separately for each individual database instance [Page
132]. You can define single backup
media [Page 150] or combine media to form a group of parallel backup media [Page 138].
Recommended Backup Media
• The recommended backup media for data backups [Page 131] are tape and autoloader.
Data may also be backed up to pipes or files.
•
are always to files (version files).
Log backups [Page
142]
Using files or version files as the backup medium only makes sense if they are written to tape
or autoloader afterwards.
You should only use pipes if you are working with an
138 .
external backup tool [Page
]
It is best always to copy the files to tape or autoloader. Only separate media can
be kept at other locations as a safeguard in the event of fire or similar hazards.
You must follow the manufacturer's recommendations on how frequently backup
media should be used.
User Manual: SAP DB 127