SCF Reference Manual for the Storage Subsystem (G06.28+, H06.05+, J06.03+)

• Altering a WRITECACHE setting of a disk partition sets the writecache setting of all the disk
partitions that are configured on the same physical disk. Changes to the other disk partitions
set the writecache setting of all their mirror disks.
• Altering WRITECACHE setting must be done only when the Storage CLIMs are free.
CAUTION: In order to prevent data loss, if a volume is configured with WRITECACHE enabled,
HP strongly recommends that the volume be protected by a cabinet or HP rack mounted UPS, which
will give HDD or SSD drives enough time to write cached data to the media after the processor
stops writing in the event of power loss.
An HP rack mounted UPS contains batteries that are auxiliary to the energy storage in the site UPS
system. Batteries have a lifespan which is likely to be shorter than that of the system the UPS supports
and they must be maintained so that they are replaced when their usable lifespan has elapsed.
The HP rack mounted UPS system includes self test capabilities which must be monitored to insure
the UPS remains capable of functioning in the event of a power loss.
The HP rack mounted UPS must be configured in OSM Service Connection. This ensures that system
processing is halted once the HP rack mounted UPS has been in use for a period of time that is
configured in SCF. The configuration should allow for ten additional minutes of rack mounted UPS
power following the issuance of the halt.
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