I don't see am EX2010 forum.

I would like to know  if its possible to have a 2nd EX2010 server in the network as a fall over. so,,we have a single domain, 2 dc's, both GC's. and 1 EX2010 server. my boss wants to have another EX2010 in the network as a fall over in case the first fails. is this possible ??

Thank You

Hi ,

Yes in exchange 2010 for mailbox servers we do have the High Availability feature called DAG .You need to add both the servers in DAG to achieve HA.

Once it is done Then i would suggest you to add those server to LB for load balancing the client connections.

If In case if you organisation is not interested to purchase HLB or software LB then you may need to go with windows NLB or windows DNS round robin method for load balancing the client connections.But still there would be some drawbacks on these methods of load balancing.

Reference Link for DAG : 

http://blogs.technet.com/b/winde76/archive/2011/03/23/step-by-step-create-a-database-availability-group-dag.aspx

http://msexchangeguru.com/2012/02/20/dag-implementation/

Yes, it is possible.

Since Exchange 2010 has 3 roles, you would plan for redundancy for each of the 3 roles.

Quick overview:

Hub Transport: this works pretty much out of the box with no further configuration. For incoming SMTP traffic works best with a load balancer.

Client Access: configure a CAS Array coupled with a load balancer.

Mailbox: set up a Database Availability Group.

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Failover is optimal with a load balancer placed in front of the two Exchange 2010 servers. On the other hand, it does increase complexity of the setup and requires some expertise to configure.

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Response to a similar question with good overview of what you would need:

https://social.technet.microsoft.com/Forums/exchange/en-US/b7c4c09b-5fe2-43f2-861f-4a635d18f5ba/high-availability-on-exchange-server-2010?forum=exchange2010

This article is rather advanced but addresses some of the misconceptions about Exhange 2010 high availability:

http://blogs.technet.com/b/exchange/archive/2011/05/31/exchange-2010-high-availability-misconceptions-addressed.aspx

The links at the bottom of the article may be useful.

Some more remarks and resources...

You might not have planned for the load balancer but it does provide for a much better solution.

A load balancer can be physical or virtual. KEMP Technologies offers some good entry-level solutions that I have worked with:

http://davidmtechblog.blogspot.com/2014/09/exchange-2010-high-availability-client.html

Two other market leaders are Citrix (NetScaler) and F5.

Yes, you can try to do this with just two servers but fail-over will be manual, clumsy and just not efficient.

That's why some sort of load balancing is really a necessity.

You're very welcome.

Please feel free to post follow-up questions.

Oh, btw, the 2010 forum is here:

https://social.technet.microsoft.com/Forums/exchange/en-US/home?forum=exchange2010