IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Communications Remarks
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up to 80%. When compression is employed for backup, the selected
parameters and algorithms must be documented and observed later during data
restoration (decompression).
Two parameters must be specified for the backup procedure: the degree of
automation and the centralisation (storage location).
There are two degrees of automation: manual and automatic.
- Manual data backup implies manual triggering of the backup procedure. Its
advantage is that the operator can individually select the interval of data
backup in accordance with the work schedule. Its disadvantage is that the
efficiency of data backup depends on the discipline and motivation of the
operator. Data backups may not be made due to illness or other reasons for
absence.
- Automatic data backups are triggered by a program at certain intervals.
Their advantage is that discipline and reliability are not required of the
operator if the backup schedule is complete and accurate. Their
disadvantage is that the backup program generates costs and the backup
schedule must be updated on changes in the work schedule otherwise
important changes might not be backed up in time.
There are two degrees of centralisation: central and decentralised data backup.
- Central data backups are characterised by the fact that the storage location
and the performance of the data backup are carried out on a central IT
system by one operator. This procedure is advantageous in that only the
operator requires thorough training and the remaining IT users are relieved
of this responsibility. Furthermore, increased centralisation of the database
allows more economical usage of data media. The disadvantage is that
confidential data might be transferred and disclosed to non-authorised
persons.
- Decentralised data backups are performed by IT users without being
transferred to a central IT system. Their advantage is that IT users are able
to control the information flow and data media, particularly if confidential
data are backed up. Their disadvantage is that the consistency of data
backup depends on the reliability of the IT user; furthermore, decentralised
procedures are more time-consuming for IT users.
Following selection of manual or automatic, central or decentralised data
backup, a suitable storage medium must be found for the backup copies. The
following parameters can be considered for this:
- Acquisition time for data media: The time required for priming data
restoration depends on the time required for identifying the data media
necessary for backup and making them available to the system. Cassettes in
a robot-system can be made available for restoration within a matter of
minutes; it may be necessary for stored tapes to first be transported in an
elaborate procedure and then cued.
- Access time, transfer rate: The time required for actually restoring the
data depends on the average time needed to access the data on the storage
medium and the rate of data transfer. Hard disks allow access to certain
files in a few milliseconds, whereas magnetic tapes must first be wound to
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IT-Baseline Protection Manual: Oktober 2000