Managing HP Serviceguard for Linux Ninth Edition, April 2009

Disk Device File
Enter the disk device file name for each SCSI disk or LUN.
This information is needed when you create the mirrored disk configuration using
LVM. In addition, it is useful to gather as much information as possible about your
disk configuration.
You can obtain information about available disks by using the following commands;
your system may provide other utilities as well.
• ls /dev/sd* (Smart Array cluster storage)
• ls /dev/hd* (non-SCSI/FibreChannel disks)
• ls /dev/sd* (SCSI and FibreChannel disks)
• du
• df
• mount
• vgdisplay -v
• lvdisplay -v
See the manpages for these commands for information about specific usage. The
commands should be issued from all nodes after installing the hardware and rebooting
the system. The information will be useful when doing LVM and cluster configuration.
Hardware Configuration Worksheet
The hardware configuration worksheet (page 310) will help you organize and record
your specific cluster hardware configuration. Make as many copies as you need.
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 supplies (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 of the
nodes should be on a single power source. If a power source supplies exactly half of
the nodes, it must not also supply the cluster lock LUN or quorum server, or the cluster
will not be able to re-form after a failure. See “Cluster Lock Planning” (page 98) 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
Power Supply Planning 97