Managing Serviceguard 11th Edition, Version A.11.16, Second Printing June 2004

Serviceguard at a Glance
What is Serviceguard?
Chapter 126
After this transfer, the package typically remains on the adoptive node
as long the adoptive node continues running. If you wish, however, you
can configure the package to return to its primary node as soon as the
primary node comes back online. Alternatively, you may manually
transfer control of the package back to the primary node at the
appropriate time.
Figure 1-2 does not show the power connections to the cluster, but these
are important as well. In order to remove all single points of failure from
the cluster, you should provide as many separate power circuits as
needed to prevent a single point of failure of your nodes, disks and disk
mirrors. Each power circuit should be protected by an uninterruptible
power source. For more details, refer to the section on “Power Supply
Planning” in Chapter 4, “Planning and Documenting an HA Cluster.”
Serviceguard is designed to work in conjunction with other high
availability products, such as MirrorDisk/UX or VERITAS Volume
Manager, which provide disk redundancy to eliminate single points of
failure in the disk subsystem; Event Monitoring Service (EMS), which
lets you monitor and detect failures that are not directly handled by
Serviceguard; disk arrays, which use various RAID levels for data
protection; and HP-supported uninterruptible power supplies (UPS),
such as HP PowerTrust, which eliminates failures related to power
outage. These products are highly recommended along with
Serviceguard to provide the greatest degree of availability.