A replica instance provides deployment-level redundancy of the primary instance. You can view, but not update, administrative data on a replica instance.
A replica instance provides the following benefits:
Real-time mirror of all user and system data
Failover authentication if the primary instance becomes unresponsive
Improved performance by load balancing authentication requests to multiple instances
Ability to deploy a replica instance at a remote location
Ability to recover administrative capabilities through replica promotion if the primary instance becomes unresponsive
Although a replica instance is optional, RSA recommends that you deploy both a primary and a replica instance. The RSA Authentication Manager Base Server license and the Enterprise Server license both include permission to deploy a replica instance.