Back up the data and redo log entries from the data and log areas of your database to data carriers on a regular basis. Backups can be carried out in the ONLINE operational state. This means that the database is available for users during the backup.
Example: Backup and Recovery
The following graphic shows an example of how you can save the database while it is running and then restore the data after a system breakdown using data and log backups.
1. Create a complete data backup of the database DEMODB to a backup medium.
2. Activate the automatic log backup. From now on, the database system continually creates log backups in backup files.
3. At regular intervals, create incremental data backups.
4. A system failure occurs due to a hardware error of the hard disk that contains the data area of the database. The hard disk that contains the log area, however, remains undamaged.
5. To restore the database, proceed as follows:
a) Replace the defective hard disk.
b) Import the last complete data backup.
c) Import the last incremental data backup.
d) Import the log backups since the last incremental data backup. If there are still redo log entries in the undamaged log area, then the database system uses these redo log entries instead of the corresponding log backups.
6. The database system restarts the database.