HP-UX System Administrator's Guide: Overview HP-UX 11i v3 (B3921-90011, September 2010)

Clustering (Multiple Servers, One Operating System)
Clustering technologies enable multiple servers to work in unison to present the appearance of
a single computing environment. Technically, each server is running its own operating system,
but they work together as if they were one.
Examples of clustering technologies include:
• Serviceguard Clusters
• Extended Campus / Extended Distance Clusters
• Metropolitan Clusters
• Continental Clusters
Serviceguard
A Serviceguard cluster is a networked group of HP Integrity or HP 9000 servers (known to
Serviceguard as nodes) having sufficient redundancy of software and hardware that a single
point of failure will not significantly disrupt service. The ability to continue operating in spite
of a software or hardware failure makes Serviceguard clusters highly available.
Technology Summary
When you configure a Serviceguard cluster, you set up as many redundancies as possible, both
in hardware and software. To provide the greatest degree of availability, Serviceguard typically
works in conjunction with other high availability products such as:
• MirrorDisk/UX
• VERITAS Volume Manager (VxVM)
• Disk arrays using various RAID levels
• HP Powertrust power supplies (Uninterruptable Power Supplies)
With Serviceguard, you configure packages (collections of HP-UX and application processes)
on the nodes of your cluster. There are three types of Serviceguard packages:
Failover The most common type of Serviceguard package is the Failover
Package. A Failover Package is installed on multiple nodes in a
Serviceguard cluster, but runs only on one node at a time. The node
running the primary copy of a Failover package is called the primary
node. Should the primary node fail, a copy of the package on another
node (known as an adoptive node) takes over with little or no
interruption in service until the primary node can be restored to
service. Multiple adoptive nodes can be defined for extra redundancy.
Multi-node Multi-node Packages run (simultaneously) on one or more nodes in
a Serviceguard cluster. A multi-node package can be configured to
remain running as long as at least one copy of the package remains
running. Multi-node packages do not fail over. HP supports them
only for specific applications.
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