Understanding and Designing Serviceguard Disaster Tolerant Architectures Fourth Edition, December 2007 (T1906-90023)

Disaster Tolerance and Recovery in a Serviceguard Cluster

What is a Disaster Tolerant Architecture?

Chapter 118

What is a Disaster Tolerant Architecture?

In an Serviceguard cluster configuration, high availability is achieved by

using redundant hardware to eliminate single points of failure. This

protects the cluster against hardware faults, such as the node failure in

Figure 1-1.

Figure 1-1 High Availability Architecture.

This architecture, which is typically implemented on one site in a single

data center, is sometimes called a local cluster. For some installations,

the level of protection given by a local cluster is insufficient. Consider the

order processing center where power outages are common during harsh

weather. Or consider the systems running the stock market, where

multiple system failures, for any reason, have a significant financial

node 1 node 2

pkg A

pkg B

pkg A mirrors

pkg B mirrors

pkg B disks

pkg A disks

Client Connections

pkg A fails

over to node 2