The Servers section indicates overall server information for the cluster:
Active Servers is the number of active servers within the current cluster configuration.
Servers Failed Over is the number of servers that have failed over due to an issue that should be investigated.
Servers Down shows the number of servers that are down and not-contactable.
Servers Pending Rebalance shows the number of servers that are currently waiting to be rebalanced after joining a cluster or being reactivated after failover.