Disaster Tolerance and Recovery in a Serviceguard Cluster

Disaster Tolerant Architecture Guidelines

Disaster Tolerant Architecture Guidelines

Disaster tolerant architectures represent a shift away from the massive central data centers and towards more distributed data processing facilities. While each architecture will be different to suit specific availability needs, there are a few basic guidelines for designing a disaster tolerant architecture so that it protects against the loss of an entire data center:

•Protecting nodes through geographic dispersion

•Protecting data through replication

•Using alternative power sources

•Creating highly available networks

These guidelines are in addition to the standard high-availability guidelines of redundant components such as multiple paths to storage, network cards, power supplies, and disks.

Protecting Nodes through Geographic Dispersion

Redundant nodes in a disaster tolerant architecture must be geographically dispersed. If they are in the same data center, it is not a disaster tolerant architecture. Figure 1-2 on page 17 shows a cluster architecture with nodes in two data centers: A and B. If all nodes in data center A fail, applications can fail over to the nodes in data center B and continue to provide clients with service.

Depending on the type of disaster you are protecting against and on the available technology, the nodes can be as close as another room in the same building, or as far away as another city. The minimum recommended dispersion is a single building with redundant nodes in different data centers using different power sources. Specific architectures based on geographic dispersion are discussed in the following chapter.

Chapter 1

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