Sun Cluster 3.1 Concepts Guide

High Availability Versus Fault Tolerance

The SunPlex system is designed as a highly available (HA) system, that is, a system that provides near continuous access to data and applications.

By contrast, fault-tolerant hardware systems provide constant access to data and applications, but at a higher cost because of specialized hardware. Additionally, fault-tolerant systems usually do not account for software failures.

The SunPlex system achieves high availability through a combination of hardware and software. Redundant cluster interconnects, storage, and public networks protect against single points of failure. The cluster software continuously monitors the health of member nodes and prevents failing nodes from participating in the cluster to protect against data corruption. Also, the cluster monitors services and their dependent system resources, and fails over or restarts services in case of failures.

Refer to High Availability FAQs for questions and answers on high availability.