Fencing is a very important concept in computer clusters for HA (High Availability). Unfortunately, given that fencing does not offer a visible service to users, it is often neglected.

Fencing may be defined as a method to bring an HA cluster to a known state. But, what is a “cluster state” after all? To answer that question we have to see what is in the cluster.

via Fencing and Stonith.

STONITH (Shoot The Other Node In The Head)