Failover Configuration

A typical failover configuration consists of a primary and secondary VMP Server, a load balancer, and a SQL server.

This table shows the behavior of each of these server nodes.

Node	Description
Primary Vocera Messaging Platform (VMP Server 1)	The primary server is accepting all HTTPS traffic. The primary server is responding with a positive acknowledgment request from the Load Balancer every 10 seconds. The primary server is updating the SQL server with a timestamp every 2 seconds.
Secondary Vocera Messaging Platform (VMP Server 2)	The secondary server is the standby server. The secondary server is not responding with a positive acknowledgment request from the Load Balancer every 10 seconds. The secondary server is retrieving a timestamp from the SQL server every 2 seconds. If the SQL timestamp table has not been updated by VMP Server 1 within 20 seconds, VMP Server 2 will automatically start its HTTP interface and begin to accept traffic from the Load Balancer.
The Load Balancer in conjunction with the VMP Server pair	The Load Balancer is sending an HTTP health check request to both VMP Server 1 and VMP Server 2. After a third response failure from VMP Server 1, the Load Balancer will start routing traffic to VMP Server 2 (This will happen once VMP Server 2 has initialized its HTTP interface and is accepting requests.).
The SQL Server in conjunction with the VMP Server pair	VMP Server 1 is updating a timestamp in the SQL Timestamp Table every 2 seconds. VMP Server 2 is retrieving the timestamp from the SQL Timestamp Table every 2 seconds.