Exchange 2013 DAG - where to place witness server?

Question

We have a setup with two Exchange 2013 servers (EX01 and EX02, every with all roles) in DAG on the single site. DAG is only for failover purposes.

I'm planning to move one server to the second datacenter.

Question: Where should i place the witness server?

Imagine disaster scenario:

Site-to-site connection is DOWN
EX01 in the primary datacenter is DOWN
EX02 in the second datacenter is UP
Witness server is located in the primary datacenter and it UP

Will DAG with EX02 will work in that scenario or it will lose quorum without connection to the witness? Should i place the witness server in the third (cloud) datacenter?

Thanks!

I might suggest you look into using a witness server in Azure. — joeqwerty, Jan 14 '20 at 13:45
Yeah. 3rd location is the obvious answer - which points to cloud. — TomTom, Jan 14 '20 at 14:08

score 0 · Answer 1 · answered Jan 15 '20 at 02:44

According to my research, when a DAG has been deployed across two datacenters, you can now use a third location for hosting the witness server. If your organization has a third location with a network infrastructure that is isolated from network failures that affect the two datacenters in which your DAG is deployed, then you can deploy the DAG's witness server in that third location, thereby configuring your DAG with the ability automatically failover databases to the other datacenter in response to a datacenter-level failure event. If your organization only has two physical locations, you can use a Microsoft Azure virtual network as a third location to place your witness server.

Exchange 2013 DAG - where to place witness server?

1 Answers1