What is the AlwaysOn equivalent of Database Mirroring's Witness
I've got some experience in setting up new synchronous Database Mirroring environments, and have done some awful, awful things in the past to get an asynchronous reporting database replica, while within the budgetary constraints for Standard edition. But I'm now part of a new project which has both HA and TDE as requirements, so we have the budget for Enterprise. This gives me an opportunity to look at AlwaysOn. While trying to get my head around the varying differences, what I can't seem to find is the equivalent of the Witness. Our existing Mirroring endeavours have always used Express to provide the Witness (for cost savings) but, as I understand it, only Enterprise can take part in AlwaysOn. I can't see how anyone could expect me to have run an extra Enterprise node just to provide quorum so, given a provisional setup of: * 2 x synchronous, auto-failover OLTP nodes * 2 x asynchronous, read-only reporting nodes * 1 x quorum-providing something ...what is 'something'?