I have a customer that is looking at putting redundant Phase 2 interfaces in separate buildings on a campus. They want to put each primary interface local to each building on workstation machines and then consolidated the secondary interfaces in a central server room which will also host the PI server. If a building becomes isolated due to a network failure, process data should buffer locally. If the primary interface hardware fails, the centrally located secondary will take over assuming the network is up. This is not a typical architecture that I see. Does anyone have any guidance or information that explains how the primary and secondary coordinate with each other (determine who is active/standby and how they would handle a situation where both are powered up and running but one can't hit the data source)? Ultimately, I'm trying to determine where to locate the shared Phase 2 file location. I believe the shared file should be as close to the data source as possible (so, it should go in the non-central buildings), but I wanted to check with others who may have seen this.
Thanks in advance for any help,