What is meant by a failover? What are the types of failover?

Failover refers to a feature exclusive to Cisco to provide redundancy. 

In case of a failover, two same ASA’s need to be connected to each other with a specific link.

The health of units and active interfaces is monitored to check if a failover has occurred.

There are two types of failover:

• active/standby failover
  
  
• active/active failover