IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Organisation Remarks
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Levels, which are listed below. Each level contains the functionalities of the
previous levels.
- SFT I (System Fault Tolerance I)
Novell Netware 3.x supports SFT I as standard. This level prevents loss of
data due to physical hard disk problems. After a write access to a file, the
stored data on the disk is compared to the still available memory image on
the Netware server. If the data do not compare, the sector of the hard disk
will be marked as faulty and will be locked for future access.
The data is then stored in a ”Hot Fox Area” on the hard disk. Within
Novell Netware this area occupies two percent of the disk as a standard.
- SFT II (System Fault Tolerance II)
SFT II can be implemented in two different ways.
- Disk Mirroring (System Fault Tolerance II)
For disk mirroring two identical hard disks are connected to the
same controller of a server. The data is stored simultaneously on
both hard disks. If one disk fails, the second disk will be used
without a loss in availability.
- Disk Duplexing (System Fault Tolerance II)
Disk Duplexing means the installation of two hard disks and their
controllers. With this mechanism not only a hard disk failure can be
remedied, but also the failure of a hard disk controller can be
recovered.
- SFT III (System Fault Tolerance III)
SFT III is the highest level of tolerance for hardware faults that arise
during operation. Two identical Novell Netware servers operate
simultaneously and parallel to one another within the network.
The servers are connected via their own high speed network. If one server
breaks down, operation of the network can be continued with the second
server almost without loss of time and data.
The decision as to whether or not additional measures will be needed besides
level I is dependent upon the required level of availability in the network.
Uninterruptible Power Supply (USP)
By using an uninterruptible power supply (UPS), the consequences of a power
failure can be remedied. Netware supports the utilisation of devices supporting
UPS-Monitoring. In case of a power failure the server will be shut down at the
end of the lifetime of the UPS in an orderly manner. All data residing in
caches are written to hard disks. Connections to servers are terminated, as are
server processes.
Additional controls:
- Is the documentation sufficient for a substitute administrator?
- How has the choice of SFT level been justified?
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IT-Baseline Protection Manual: Oktober 2000