Loadbalancer.org glossary
Clustered pair
What is a clustered pair?
A clustered pair is a pair of appliances working in Active-Passive mode. The active unit (normally the Primary) handles all traffic under normal circumstances. If the active unit fails, the passive unit (normally the Secondary) becomes active and handles all traffic.
We always recommend deploying Loadbalancer.org appliances as a clustered pair to provide high availability and to avoid introducing a single point of failure.