I am designing an Exchange 2013 Site Resilient Scenario with two Multi Role Exchange Servers per Site. There are Two Sites.
This is a small organization, 400 users and all must be virtualized. A single forest, Two Sites 50/50 users each Site. There is a third Site for Witness Server collocation.
Our goal is to have redundancy per individual Site and Site Resiliency. Multi Role or Dedicated CAS it's my question. I don't have load balancer, budget is a key factor. If dedicated CAS was chosen, we would have eight exchange servers total.
My dream design is precisely two multi Role Servers per Site, four total. One DAG stretched across both sites. One third site for witness folder collocation.
Zero load balancers and my understanding is that ‘Single Global Namespace Support’ , Round Robin and one stretched DAG in Exchange 2013 will do the magic and it'll keep connected users even when local datacenter is down (Further manual DNS changes would be obviously necessary after the crash to avoid sporadic connectivity loss).
My question is:
1. Will be all my goals accomplished deploying only four Exchange Multi Role servers (Two per Site) in these locations? Or having dedicated CAS would make a difference?
2. Even I don't want load balancer (NLB or virtual-hardware load balancer). Is this a must?
3. In this scenario I pretend to use nothing but Standard versions of Exchange 2013 and Standard versions of Windows 2012/R2. Is there any reason why having Enterprise Edition would improve or validate my design?
Thanks for your help.
This is the scenario