Managing Serviceguard Eighteenth Edition, September 2010

Name of Name of Node IP Traffic
Subnet __Blue___ Interface ___lan2___ Addr_______________ Type _standby_
Name of Name of Node IP Traffic
Subnet __Red____ Interface ___lan1___ Addr___35.12.15.12_ Type _HB, client
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Disk I/O Information for Shared Disks:
Bus Type _SCSI_ Slot Number _4__ Address _16_ Disk Device File __________
Bus Type _SCSI_ Slot Number _6_ Address _24_ Disk Device File __________
Bus Type ______ Slot Number ___ Address ____ Disk Device File _________
Attach a printout of the output from the ioscan -fnC disk command
after installing disk hardware and rebooting the system. Mark this
printout to indicate which physical volume group each disk belongs to.
Power Supply Planning
There are two sources of power for your cluster which you will have to consider in
your design: line power and uninterruptible power sources (UPS). Loss of a power
circuit should not bring down the cluster.
Frequently, servers, mass storage devices, and other hardware have two or three
separate power supplies, so they can survive the loss of power to one or more power
supplies or power circuits. If a device has redundant power supplies, connect each
power supply to a separate power circuit. This way the failure of a single power circuit
will not cause the complete failure of any critical device in the cluster. For example, if
each device in a cluster has three power supplies, you will need a minimum of three
separate power circuits to eliminate electrical power as a single point of failure for the
cluster.
In the case of hardware with only one power supply, no more than half the nodes
should share a single power circuit. If a power source supplies exactly half the nodes,
it must not also supply the cluster disk lock or Quorum Server, or the cluster will not
be able to re-form after a failure. See the section on cluster locks in “Cluster
Configuration Planning” for more information.
To provide a high degree of availability in the event of power failure, use a separate
UPS at least for each node’s SPU and for the cluster lock disk (if any). If you use a
Quorum Server, or quorum server cluster, make sure each quorum server node has a
power source separate from that of every cluster it serves. If you use software mirroring,
make sure power supplies are not shared among different physical volume groups (or
VxVM disk groups); this allows you to set up mirroring between physical disks that
are not only on different I/O buses, but also connected to different power supplies.
To prevent confusion, label each hardware unit and power supply unit clearly with a
different unit number. You can use a Power Supply Worksheet such as the one that
follows to record the hardware units you are using and the power supply to which
they will be connected; record the following information:
128 Planning and Documenting an HA Cluster