The Vocera Messaging Platform is designed to support clustered environments using active server and passive server configuration.
In a clustered environment, the primary server:
Secondary nodes retrieve a timestamp from the SQL server every two seconds, but stay passive unless the primary node has not updated the SQL server timestamp in the last 20 seconds, at which point the primary node is assumed to have failed. The load balancer manages the status of each VMP Server by sending a health check request to the primary and secondary nodes. The load balancer redirects traffic to a secondary node after a third missed heartbeat from the primary node.