User's Manual

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provides one single and unique point-in-time to be restored later. Once the offline backup
exists, the log files in the infinite archive directory become obsolete and may be removed.
The other option comes with no warranty whatsoever. The option is to keep 7signal
Sapphire running and to delete log files in the infinite archive directory. To understand what
files are likely to be unused, the active log files has to be followed to see the time to fill up a
single log file and then deduce what infinite archive files might be available for deleting . If
one chooses this option, setting the safety margins reasonably high is advisable.
NOTE: In case there is both a system crash and a log file has
been deleted too early, the recovery shall never be able to
finish. In this case, the only consistent system stage is
available at offline backup time.
NOTE: The automated reporting lessens the impact of possible
data loss if used in detail and frequently. However, possibility
to measurement drill-in analysis is lost as well as any change
in the network topology and other management information.
The infinite archival logging is provided in order to support online backups (see below) but it
should also be seen as a method to make system run longer automatically without user
interruption. However, the system has to be maintained and administered. It is outside of
the scope of this document to fit 7signal Sapphire to IT processes of all organizations but
offline backups with planned system halts are highly recommended.
Backup method options
Default state
Essentially the 7signal Sapphire system default state is not a backup system at all but it is
based on the underlying database management system's robustness, fault tolerance and
basic level recovery options. In case of a permanent disk failure the data is lost. By installing
the databases on RAID disks lessens the risk further.
On default state the 7signal Sapphire relies on the database management system (IBM DB2)
logging. The assumptions are that the management information (Eye, access point and
target network) changes are not continuous but rather sporadic. The measurements are
continuous but losing few of the most recent samples is a risk that can be tolerated. Typical
starting point for analysis is one week of measurements and in case of sudden system down
one would lose the data until the system is fixed. And in case of system down it is expected
that all the efforts shall be there to bring 7signal Sapphire and other systems online again.
There shall be no special snapshots where to start operations again. It is possible to resume
a state before the interrupt, possibly the system is operational with no special effort at all.
Offline backups are possible but require user actions both to shutdown 7signal Sapphire and
do the actual backup.
Method handicaps: