The two components that affect the time a failover will take to complete are as follows:
1. The time taken for the passive server to react to the failure of the active server. This is defined as the product of the amount of heartbeats the active server is allowed to miss before a failover is initiated (by default 3 heartbeats) and the time period at which heartbeats are issued (by default 20 seconds)
2. The time taken to start the protected application on the new active server.