IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Communications Remarks
____________________________________________________________________ .........................................
S 6.51 Restoring a database
Initiation responsibility: Head of IT Section, IT Security Management
Implementation responsibility: Administrators
It is necessary to prepare a concept describing how database backups are to be
restored. This concept must be structured in accordance with
- The data backup policy (refer to S 6.49 Data backup in a database) and
- Potential error situations creating a need for the restoration of data
backups.
These two aspects should be used as a basis for determining which database
backups are to be restored using which techniques.
The restoration of a database is a complex task which must be performed
carefully by experienced personnel. In spite of this, errors and hitches must
always be reckoned with during a restoration. For this reason, a damaged
database should not be overwritten simply by restoring the database backup.
In many cases, a seemingly corrupt database can be fixed again. In order to
minimise the restart time however, trouble shooting should be accompanied
by an attempt to restore the database in a separate storage area. Even if
damaged data can no longer be repaired, it should be retained so that it can be
analysed and the cause of the error can be determined.
During restoration, the database backup should therefore first be loaded on a
separate storage medium. Here, it must be noted that the backup requires the
same amount of disk space as the defective database.
This disk space must be reserved for emergencies, in order to prevent a loss of
database integrity and meet availability requirements. If this is not possible, it
is necessary to determine a technique whereby the required disk space can be
made available at short notice. Naturally, this should not result in an additional
loss of data, for example if areas of the hard disk holding other data need to be
overwritten in order to release the resources necessary for loading the database
backup. If data nevertheless needs to be deleted due to a lack of disk space, it
must first be backed up carefully to ensure that it can be made fully available
again after restoration has been completed.
If only individual data records need to be restored instead of the entire
database, the backup data should always be loaded separately from the
original data. Corresponding disk space must be available in this case, too.
Here, it is more advisable to configure a separate database so as to ensure that
the original database remains unaffected at all events. This applies even if it is
possible to read the backup data individually into the original database.
Additional controls:
- Has a concept for the restoring of database backups been prepared?
- When was the restoring of database backups last rehearsed?
- Has enough disk space been reserved for emergencies?
____________________________________________________________________ .........................................
IT-Baseline Protection Manual: Oktober 2000