Exchange 2010 CAS HA

Hi everyone, i am a bit confused here. We have 2 CAS servers, both are a part of Windows NLB. But our Outlooks point to one CAS server at a time. I had my account on CAS02 and I shutdown CAS02 just to test and my Outlook couldnot work and it didnt go to CAS01 automatically. I dont see any errors or anything on any of the servers and the NLB is working fine. Any idea what could be wrong ?
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Exchange UserSystems AdministratorAsked:
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Ben HartCommented:
While you can use NLB for Exchange I def wouldn't.  That said all members of an NLB cluster must be identical.  Check your nic and nlb configs as per: http://www.kraftkennedy.com/configuring-nlb-for-exchange-2010-cas-load-balancing/

Then verify your ClientAccessArray is configured correctly: http://exchangeserverpro.com/exchange-server-2010-cas-array/
Exchange UserSystems AdministratorAuthor Commented:
CAS array had been setup and configured all fine. But we upgraded from SP1 to SP3 and after that the cas array somehow disappeared. I can still ping it though but I cannot see the A record of it. And the servers and databases are not picking it up. Can I reconfigure it ?
Ben HartCommented:
With Exchange, every service pack totally removed the application and reinstalls it.  I had SP2 bombout and bork up one of my servers a few years back. After that I didnt do SP's unless I had to.
Sounds like you need to reconfigure this portion.
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Exchange UserSystems AdministratorAuthor Commented:
The cas array's site is the default-first-site while my exchange servers are at another site. Do you think this would be an issue ? During the upgrade, we also setup a new site for the company and we removed all DCs from our default first site and created 2 different sites for the DCs. There is no DC or exchange server in the default first site. Do you think this could be an issue ?
Ben HartCommented:
You should be able to follow that second link and get her set back up.
Ben HartCommented:
That's a possibility, can you change the site in Exch?
Exchange UserSystems AdministratorAuthor Commented:
I got the idea of the site from the 2nd link you sent me. Just need to confirm with you if the site could be an issue ? I can simply change the site by the set-clientaccessarray ?
Ben HartCommented:
I believe that's the correct cmdlet, but yes matching the sites is the first thing I'd try.
Will SzymkowskiSenior Solution ArchitectCommented:
First off NEVER use WNLB in a production environment. If you have it working your lucky and it will not function like a typical hardware load balancer.

Second
The cas array's site is the default-first-site while my exchange servers are at another site. Do you think this would be an issue ?

A CASArray is not a load balancing mechanism and needs to be used hand in hand with an actual load balancer. You also need to make sure that you have one CASArray for every AD Site where you are hosting Exchange. CASArray's have AD Site Boundary's which means they do not operate outside of its over AD Site.

Third
During the upgrade, we also setup a new site for the company and we removed all DCs from our default first site and created 2 different sites for the DCs. There is no DC or exchange server in the default first site. Do you think this could be an issue ?

Where ever your are hosting Exchange (AD Site) you are *REQUIRED* to have at least 1 Read/Write DC/GC/DNS server present. If you do not have this Exchange will not work period.

I would suggest that you take another look at your environment and see how it is actually configured and start by checking the logs to see if you can get any additonal information.

Will.

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Exchange UserSystems AdministratorAuthor Commented:
Thanks Will.

We do have 3 DCs on the site 'A' where our Exchange is present currently. But the cas array is on default first site (not site A)

So if I move the casarray to site A, will it start working ?

And I know that NLB is not good but I recently joined this company and the environment was already there. what is the best load balancing option you would suggest ? And how easy it would be to get rid of NLB and join the 3rd party LB without any disruptions ?
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