I am going to implement Database avalability group in exchange 2010.
Currently I have two exchange servers. Both have Hub transport, Mailbox server and CAS role installed.
I want to know following things.
1. which role I have to install at third server which I will use as a witness server?
2. What will happen if witness server goes down? If only witness server goes down will mail box server will remain up or mailbox server also down?