Failover
From CasGroup
Failover means the automatic substitution of a functionally equivalent system component for a failed one: if one fails the other can take over. The principle describes the transfer of operation from a failed component to a similar, unused and redundant component to ensure uninterrupted functionality. It happens automatic without human intervention, and is often found and used in fault-tolerant architectures. Necessary for successful failover techniques is high redundancy.