In a very large AD/exchange environment, we are increasingly having issues with Unity after an exchange server is rebooted. We have Unity 4.2.1 and 4.05 deployed, each with unity subscribers across multiple exchange servers. There does not seem to be any consistency with Unity when rebooting exchange servers. Sometimes, Unity recovers seemingly without issue after a partner or associated exchange server is rebooted, other times, we have to stop and restart the Unity services in order to get message delivery and MWI working, and occassionally, we need to go as far as rebooting both unity and the exchange server which unity has lost communication with to resolve the issue. With so many unity and exchange servers, this gets very high visibility with the customer as they always report "Unity is down/not working"..
The troubleshooting guide states only "When you shut down and restart Microsoft Exchange on the Cisco?Unity server, Cisco?Unity may need to be restarted manually." but does not give any detail as to what the dependancy is. Can someone please tell me what we need to do from a unity perspective in order to be able to recover from exchange reboots without having an incident declared by the customer? Other than monitoring the event logs for errors, is there something we can do to be more proactive?