Configuring and Managing Clusters / About Vocera Voice Server Clusters |
A cluster member uses discovery mode to determine whether it should come online as the active node or a standby node.
A cluster member enters discovery mode in any of the following situations:
The first time it comes online as a cluster member.
Any time it does a full restart.
Any time it loses contact with the active node.
If it cannot find a network route to the active node.
If the active node fails to service a poll from a standby node.
Each standby node in a cluster polls the active node periodically to draw down synchronization transactions. If the standby node does not receive a response within 10 seconds, it assumes the active node has failed and it goes into discovery mode to find out the status of other nodes in the cluster.
After entering discovery mode, a server takes one of the actions shown in the following table, depending on the status of the other cluster members:
Status of other Cluster Members |
Action Taken by Server in Discovery Mode |
---|---|
One cluster member is already active. |
The server comes online as a standby node. |
No cluster member is active and no other server is in discovery mode. |
The server comes online as the active node and takes control of the cluster. |
No cluster member is active and one or more other servers are in discovery mode. |
The rankings on the Cluster Setup page of the Server screen serve as a tie-breaker. |