You can extend the availability of your hardware by providing
battery backup to your nodes and disks. HP-supported uninterruptible
power supplies (UPS), such as HP PowerTrust, can provide this protection
from momentary power loss.
Disks should be attached to power circuits in such a way that
mirror copies are attached to different power sources. The boot
disk should be powered from the same circuit as its corresponding
node.
In particular, the cluster lock disk (used as a tie-breaker
when re-forming a cluster) should have a redundant power supply,
or else it can be powered from a supply other than that used by
the nodes in the cluster. Your HP representative can provide more
details about the layout of power supplies, disks, and LAN hardware
for clusters.
Many current disk arrays and other racked systems contain
multiple power inputs, which should be deployed so that the different
power inputs on the device are connected to separate power circuits. Devices with
two or three power inputs generally can continue to operate normally
if no more than one of the power circuits has failed. Therefore, if
all of the hardware in the cluster has 2 or 3 power inputs, then
at least three separate power circuits will be required to ensure
that there is no single point of failure in the power circuit design
for the cluster.
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