The key difference between these two architectures is performance. The two main types of high-availability (HA) clusters are:
Active-active clusters: Client machines connect to a load balancer that distributes their workloads across multiple active servers.
Active-passive clusters: Client machines connect to the main server, which handles the full workload, while a backup server remains on standby, only activating in the event of a failure.
Active-active clusters give you access to the resources of all your servers during normal operation. In an active-passive cluster, the backup server only sees action during failover.