Managing Serviceguard Eighteenth Edition, September 2010

Figure 2-4 Cluster with Fibre Channel Switched Disk Array
This type of configuration uses native HP-UX or other multipathing software; see
“About Multipathing” (page 45).
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 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.
Redundant Power Supplies 49