User Guide

SAP AG November 2002
log area [Page 142] or the log backup [Page 142] (if the information in the log area is
insufficient).
Backup Strategy
One key element of the security concept [Page 37] for your database system is the regular
backing up of your data. You should therefore carry out the following backups [Page 126] at
regular intervals: data backups [Page
131] and log backups [Page 142].
You can use external backup tools [Page
138] to reduce the time needed for backup.
Data Backup
Note that, in the case of a recovery, a more up-to-date data backup means that fewer log
entries need to be reproduced. Therefore, carry out data backups as often as possible.
• Carry out a complete data backup [Page
40] every productive day.
• If you cannot or do not want to carry out a data backup every day, you should at least
carry out an incremental data backup [Page
41] every productive day.
If complete data backup is active, incremental data backup cannot be started.
You can carry out data backups in parallel to reduce the time required for the backups.
Log Backups
• Automatic log backup [Page 126]
The automatic log backup (autosave log mechanism) should always be active.
Complete and incremental data backups are also possible while the automatic log
backup is active.
• Interactive log backup [Page
139]
You should save the log entries every productive day.
If automatic log backup is not active, you must regularly check that there is enough
storage space available in the log area [Page
142]. If necessary, back up the log area
immediately by starting an interactive log backup. If new log entries cannot be written
to the log area because there is not enough storage space, the database stops.
• Archiving of version files [Page
153]
You should regularly archive the version files written during a log backup to a medium
of your choice. Once archiving has been carried out successfully, you can delete the
version files written during the log backup, and thereby ensure that there is enough
space available in the directory for version files.
If you use an external backup tool [Page 138], you can automate the archiving of
version files. To do this, follow the instructions in Archiving Version Files of the Log
Area [See SAP DB Library].
Tapes containing data or log backups should not be directly overwritten with the
next backup. If you retain, say, the last four backup generations, it may be
possible to use an older backup if a media failure occurs.
User Manual: SAP DB 39