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We want to introduce Exchange 2010 in our organization.

We have 2 locations:

  • Main location has 2 ISP links used with one Forefront TMG 2010 (100 people on site)
  • Second location has 1 ISP link with normal router (from 5 to 20 people on site, depending on which location will be chosen for 2ndary).

We also are Microsoft partners so we have some Microsoft licenses for free which is:

  • 2 x Exchange 2010 ENT

What would be the best way to go from here considering that:

  • We need redundancy for hardware (if our servers in main locations go down, we would like people to use our secondary location - even people that are in the main location),
  • We need redundancy for ISP (if our main location looses Internet access people from outside/2nd location should be able to access their mailboxes in secondary location without problem, and all emails should be comming there),
  • We need redundancy in case of power failure which basically means similar situation to hardware failure.

Good to know:

  • There's permanent VPN tunnel with one ISP link between 2 locations
  • We have two AD controllers 2008 R2 in main location and no AD controllers in 2nd location
  • There are about 170 people working from home / other sites / client workplaces

What we can eventually do if necessary:

  • Setup AD in secondary location,
  • Buy few (1,2,3,4) additional licenses (preferably later on then in the beginning, but if it will be problematic to extend things as we go) the more licenses we have to buy the bigger problem it gets (this is supposed to be cost-effective :/)

What we need:

  1. If location A servers go down all users can use their mail as normal from location A and B and from Internet
  2. If location A internet links go down mails need to keep on coming (2 x MX records - 1 per location?) to second location and people in location B and Internet can still work on their emails, when location A connects back up no mails are lost and things get back to normal..

I would like to achieve best possible solution we can get in terms of redundancy and operation results. I would like to use DAG and 2 entry points (1 MAIN, 1 SECONDARY) in case of link problems and any power/hardware failures. Costs does matter.

PS. I asked similar question a while back but licenses have changed so this may affect your judgement.

share|improve this question

Have you looked at using Office 365, or perhaps a hybrid approach? You can pawn off particular roles, or even just duplicate roles up in the 365 cloud - which could give you the redundancy you're after. Its relatively cheap (or free in some partner agreements), would mean that you can deploy the two licenses you have at your main office and go from there.

As for your topology, you're probably best (for your amount of users) to go with a single server powering all clients internally. Unless you need Unified Messaging which should probably be installed on its own. Then you could replicate all those roles for redundancy in the Office 365 cloud.

share|improve this answer
Well Office 365 is one of possibilities but I guess that's why we have 2 locations. We have 2 free ENT licenses and over 100 CAL's. So that just means one time buy of additional STD ENT licenses and some CAL's. I was more looking into advice how DAG will behave and what I need to achieve redundancy. – MadBoy Aug 4 '11 at 6:21
The second location is only there for server redundancy? – Ashley Steel Aug 5 '11 at 4:25
Basically yes. We don't want to loose emails, have people stop working if a) both links at main location go down, b) power goes out c) hardware crashes – MadBoy Aug 5 '11 at 6:29
Without the links at the main location I think its going to happen regardless. Only way to get around that would be going with a cloud service like Office 365, at least for your external users, or if you have a separate backup DSL connection or something for your internal users. – Ashley Steel Aug 9 '11 at 6:19
Hi @MadBoy - what did you end up doing? – Ashley Steel Oct 2 '11 at 9:56

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