If a media failure occurs on the system devspace or a data devspace, database operation ends (unless the data devspaces and the system devspace are mirrored). After repairing the media failure, the database must be restored using the last complete backup version (Backup / Restore / Data).
If the archive log had not been saved in the meantime, the restart has the effect that the database modifications recorded in the archive log are reapplied, thus reestablishing the last consistent state of the database.
If the archive log had been saved in the meantime, Backup / Restore / Data must be performed and the backup of the archive log must be restored with Backup / Restore / Log (UNTIL) "troubleshooting when problems occur".
If the database needs to be reset to a previous state for organizational reasons, the most recent complete backup (Backup / Restore / Data) that was made previous to the desired date and time must be restored, the current archive log must be saved, and the log backups subsequent to the complete backup (Backup / Restore / Log (UNTIL)) must be restored. The desired database state can be determined by specifying a date and a time (Backup / Restore / Log (UNTIL)).
For a recovery using modified database pages instead of log backups, a similar procedure is used. A sequence of Save / Updated Pages tapes written after the last complete backup will also be availabe in this case. The tapes must be restored one after the other with Backup / Restore / Updated Pages. The current contents of the archive log do not need to be saved; they are used to reestablish the last consistent database state during the following restart.
If a media failure occurs on the transaction log devspace or one of the archive log devspaces, database operation ends unless the log mode DUAL defines a mirrored archive log. After repairing the media failure and performing RESTORE LOG FROM DEVSPACE and a subsequent restart, the database is in a consistent state again.