Managing Serviceguard 12th Edition, March 2006

Understanding Serviceguard Hardware Configurations
Redundant Power Supplies
Chapter 2 53
Redundant Power Supplies
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 different supply than 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.