High availability
From Freephile Wiki
Just some quick notes for later expansion
The Linux High-Availability project at www.linux-ha.org is the resource for High Availability with free software. Failover is the part of a Highly Available system when primary resources automatically switch to reserve or stand-by resources.
See their downloads page for Heartbeat, Cluster Glue and Resource Agents
A leading company in this space is Cluster Labs See their github projects