Exchange 2010 CAS Array - 2 Sites

So here is what I have done.. I'm really hoping someone can give me some feedback here that has more knowledge in this area:

 

 

SITE A:

 

 

* Created a CAS array with FQDN of "array-siteA.domain.com"

 

 

SITE B:

 

 

* Created a CAS array with FQDN of "array-siteB.domain.com"

 

 

On the LTM's at each side there are three VIP's which handle RPC - one for MAPI, one for Address Book, and one for the RPC endpoint mapper. These VIPs are fronted by GTM's at each location, and the Wide-IP for this service is "array.domain.com." Then, I simply created two CNAMEs for "array-siteA" and "array-siteB" to point to "array.domain.com" Therefore, array.domain.com points to whichever site is active at the moment as determined by GTM.

 

 

Does this sound correct?

Hi Josh,

 

 

Your configuration sounds correct.

 

 

As an aside, what version of GTM are you running?

 

 

Cheers,

 

Helen

Thanks, Helen! We are running 10.2.2.763.

Okay.

 

 

I'd test this out, and if you have any trouble, have a look at support.f5.com, using the search parameter of CNAME and 10.0.0.

 

 

Cheers,

 

Helen

Hi Josh,

 

 

I can maybe see that configuration working, as long as you are strictly running in an active/passive setup. Otherwise, if you were ever to activate individual database copies in Site B (active/active), you would not have the flexibility of forcing client connections to the respective CAS array for that site.

 

 

The only other concern I have is if you are doing Kerberos authenitcation to the CAS array. I'm not sure if anything will break if the Outlook client obtains a ticket for array-siteA.domain.com, but is then redirected to array.domain.com, if that will break anything in the Kerberos authenication process. It may not be a big deal if you are not using Kerberos, but something to be sure to test, if you are.

 

 

The proper way to achieve this, I think, is to have separate CAS arrays for each site with separate namespaces, and as a part of the datacenter switchover process, update the DNS A record for the CAS array in Site A to point to the same VIP as the CAS array in Site B. I realize this makes a datacenter siwtchover a manual process, but per Microsoft, datacenter switchovers in Exchange 2010 are not automatic.

 

 

Adam

Adam,

 

 

Thanks for the advice. I do see what you are saying about active/active scenarios and how this would present a problem. For us, siteB is purely a DR site. There will be no active mailboxes on this site unless siteA is unavailable.

 

 

I do feel like this is somewhat of a "hack," but I'm about to start testing, and I'll report back here with results.

 

 

Thanks,

 

 

Josh