DAG - How will this work? (Full Version)

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ace1701 -> DAG - How will this work? (2.Aug.2010 9:35:06 AM)

I'm trying to find an answer to what I thought was a simple question.

To keep it simple letís say I have a 2 server Dag with 1 database. Both servers have all Exchange roles installed.

Server A: Active Database
Server B: Inactive Database

Letís say I need to take Server A down for maintenance so I switch the Active Database to Server B.

Question: Will the CAS on Server A let the Outlook clients know to point to Server B so that I can bring Server A down?

Or will everyone break once A goes down?


John Weber -> RE: DAG - How will this work? (2.Aug.2010 1:42:42 PM)

You gotta load balance the CAS.
DAG requires that you use either off-server hardware to LB the CAS roles or move the CAS to another set of servers.

praveenbalan -> RE: DAG - How will this work? (2.Aug.2010 2:04:33 PM)

Hello mate,

Add to what John said,
1. Create a CAS array and configure Load balancing
2. set rpcclientaccessserver property of each database to the newly created cas array name(only if the databases were created before the array).
you may get more details here - http://www.gilham.org/Blog/Lists/Posts/Post.aspx?List=aab85845-88d2-4091-8088-a6bbce0a4304&ID=733&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A%20gilhamconsulting%20%28Gilham%20Consulting%20Blog%29

ace1701 -> RE: DAG - How will this work? (2.Aug.2010 2:04:57 PM)

Your saying I can't have the CAS installed on the same servers that I want to run DAG on?

ace1701 -> RE: DAG - How will this work? (2.Aug.2010 2:10:01 PM)

Can I have the CAS array on the same servers as the MB and the DAG?

jjfbcn -> RE: DAG - How will this work? (2.Aug.2010 2:15:52 PM)

If you let me, I'd like to introduce another question in this thread.

Let's suppose we have 2 multi-role servers, ht,cas, mb. May I balance the CAS with a linux load balancer as Pound?

praveenbalan -> RE: DAG - How will this work? (4.Aug.2010 11:42:15 PM)

Hi Mate,

you can very have the CAS role installed on an MB server which is part of a DAG. And if you want to configure cas array you should use a thirdparty load balancer. Because CAS array required NLB, whereas DAG uses failover cluster, 2 form of cluster can not run on the same box.

Hope this is clear now.

ehyates -> RE: DAG - How will this work? (2.Sep.2010 9:55:11 AM)

Absolutely.  Any offserver load balancer will do the job.  You just can't have two forms of server-side load balancing (DAG and NLB) running on the same box.  Replace NLB with an offserver load balancer, you have a functional config.

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