VTS/IS License Clusters
A cluster is defined as the list of machines configured in the VTS Internet Setup dialog. These must be computers running VTS that can see each other via VTS Remote Procedure Calls (RPC). For example, the following image shows a cluster consisting of three servers: Bridge, EngineRoom and TankMonitoring.
To configure a cluster, you need only add the server computers to the list. All other configuration and operation tasks are handled automatically.
Note: You can switch off this behavior and manage connections on a machine-by-machine basis by setting the Setup.INI variable, ManualVICServerLists to 1.
Cluster members share information about all the connected VIC sessions across the cluster, along with license and configuration details. Updates to either the Realms or the Server Setup list on any one machine in the cluster are automatically propagated to all. Changes in timeouts or mode are automatically sent to all VIC sessions.
License counts are combined within a cluster. You can connect more clients to a server than would otherwise be allowed by its license limit, so long as the total number of connections within the cluster does not exceed the cluster’s limit. In theory, any one machine could support all the connections available within the cluster’s limits, although in practice this may exceed that machine’s CPU or RAM limitations.
If a server fails, you do not lose its license count from the total during the time it is offline. All VIC connections to that machine are immediately re-routed to the remaining servers in the cluster that are running the application, even if this would exceed the licenses available on just those remaining machines.
If sub-networks within the organization become isolated such that the servers are temporarily unable to communicate with each other, each server will maintain the full license compliment of the cluster, even though this may exceed the license limit of that one machine.
When isolated servers re-join the cluster, if the combined total number of connections exceeds the cluster limit, no new connections can be made, but existing connections in excess of the limit are maintained.
While the cluster maintains excess connections, an event will be logged in the alarm history every 10 minutes, warning of this state.
Realm session limits are maintained across a cluster such that the total number of connections to a realm throughout the cluster may not exceed the configured limit.