You can make multiple license servers available to clients by configuring them with their own unique licenses. You configure the designation of Primary and Secondary license servers from the client side establishing the connection. A license request is first sent to any servers configured as a Primary server. If the Primary server is not available or has no connections available for the licenses it manages, the request is sent to license servers configured as Secondary license servers. If the Secondary license server has a connection available, the connection is established using the license(s) the Secondary server manages. See the License Configuration help for more information about configuring clients to use Primary and Secondary servers.
With the StarLicense service installed on multiple computers, you also can configure license servers to provide backup (failover) services for each other. The backup license server monitors the status of the Primary server it is designated to provide failover services for and, if the server fails or the service is stopped, the backup license server begins responding to requests for licenses that the Primary server manages until the Primary server is available again. If the maximum number of connections is reached while the failover server is providing the license service for the Primary, the failover server will reject requests for new connections---the licenses that the failover server is managing are not made available to clients attempting to connect to the Primary license server. The status display in the Licenses pane indicates whether a license is configured for failover and whether the license is being serviced by the Primary or a failover license server, as described in Viewing License Information.
To configure license servers to provide failover services:
From the left pane of the StarLicense Manager console, select the license server that you want to configure to be a backup license server for another StarLicense server.
Click the 
button in the Toolbar or right-click and select the Configuration command.
Click the Failover tab.