ClearSCADA Mobile Server is able to communicate with a single ClearSCADA Mobile Companion for a single system. In a redundant system with multiple ClearSCADA servers, where each server has a Mobile Companion installed, Mobile Server needs to pick the Mobile Companion to connect to. Mobile Server does not necessarily need to connect to the Mobile Companion running on the main server. It is also possible for Mobile Server to connect to Mobile Companion running on a standby machine. It is a preferred option as it diligates the additional load caused by Mobile to the standby server.
Mobile Server connects to Mobile Companion based on the Priority configured for each Mobile Companion. Mobile Server connects to a Mobile Companion with a higher priority. Mobile Companions are connected to in ascending order. For example, a Mobile Companion with priority of 1 will be preferred to a Mobile Companion with priority of 2 since the Mobile Companion with priority of 1 is higher in priority.
To enhance redundancy, it is also possible to install Mobile Server on a separate machine. In this case, Mobile Server would not depend on a particular ClearSCADA host and would connect to the next availble Mobile Companion with the highest priority should a server that hosts the currently connected Mobile Companion fail.