Configuring a Clustered Installation for Failover
The objective is to take a standard application installation on one node, detect failures, disable the first node, enable a second node, and start an identically configured application. The exact mechanics of this process will vary, depending on the hardware and software involved.
The simplest approach to availability (conceptually, though not necessarily to implement) is to use more than one server (with all of the redundancy covered previously in this document). With this method, any time one server fails, the other server simply takes over. This is called failover.