HP-UX System Administrator's Guide: Routine Management Tasks

have the software support that enables and controls the transfer of applications to
another server or network after a failure. Serviceguard provides the following support:
• In the case of LAN failure, Serviceguard transparently switches to a standby LAN.
• In the case of a node failure, an application is automatically transferred from a
failed processor to a functioning processor and in a minimum amount of time.
• For software failures, an application can be restarted on the same node or another
node with minimum disruption of service.
The primary disadvantages for Serviceguard are the additional cost of software and
hardware redundancy and the added complexity of administration. Also, hardware
failures on shared components may adversely affect all systems that are jointly
connected.
Serviceguard is an excellent choice for high availability data protection. It may be used
in conjunction with other high availability products.
HP References
Managing Serviceguard
http://www.hp.com/go/enterprise
Serviceguard Features
Serviceguard Automatic Rotating Standby
Using a feature called automatic rotating standby, you can configure a cluster that lets
you use one node as a substitute in the event a failure occurs. Any package would fail
over to the node containing the fewest running packages.
HP Reference
Managing Serviceguard, Chapter 3.
Serviceguard Rolling Upgrades
To reduce the amount of time needed for HP-UX operating system upgrades as well
as application upgrades and patches, you can provide what is called a rolling upgrade.
For a system with many components, the typical scenario is to bring down the entire
cluster, upgrade every node to the new version of the software, and then restart the
application on all the affected nodes. For large systems, this could result in a long
downtime. An alternative is to provide for a rolling upgrade. A rolling upgrade rolls
out the new software in a phased approach by upgrading only one component at a
time without bringing down your clusters. This process can also be used any time one
system needs to be taken offline for hardware maintenance.
HP Reference
Managing Serviceguard, Appendix E.
Using Serviceguard 211