A failover cluster is a group of servers that work together to maintain high availability of applications and services
A failover cluster is a group of independent computers that work together to increase the availability and scalability of clustered roles
The clustered servers (called nodes) are connected by physical cables and by software. If one or more of the cluster nodes fail, other nodes begin to provide service (a process known as failover). In addition, the clustered roles are proactively monitored to verify that they are working properly. If they are not working, they are restarted or moved to another node.