Additional Backend Server can be added to the Cluster at any moment. They should be pre-configured in the exactly the same way as the first Backend Server was configured.
To add a Backend Server to your Dynamic Cluster, start it with the --ClusterBackend Command Line option (it can be added to the CommuniGate Pro startup script). The Server will poll all specified Backend Server IP Addresses until it finds the active Cluster Controller.
Use the WebAdmin interface to verify that the Backend Server is running. Use the Domains page to check that all Shared Domains are visible and that you can administer Accounts in the Shared Domains.
When the Cluster Controller and at least one Backend Server are running, they both can serve all accounts in the Shared Domains. If you do not use Frontend Servers, load-balancing should be implemented using a regular load-balancer switch, DNS round-robin, or similar technique that distributes incoming requests between all Backend Servers.