Hi,

Im in the process of setting up high availability for our BES servers in our environment. Ive got a quick question about the exchange component.

Im thinking of setting up two exchange servers will all roles in two sites. ExchSrvr1 in SiteA, and ExchSrvr2 SiteB. Ill setup AD sites, and as such, the resources in SiteB will automatically use the CAS server in SiteB (ExchSrvr2). For the mailboxes, ill setup a DAG (probably active/passive).

So In the event the prod site (SiteA) goes completely dark, the DAG will failover, and actively mount the database on ExchSrvr2 in SiteB. On the same note, BES itself will also failover. Will BES now automatically resume mail flow and utilize the exchange server in SiteB, or will it look for the CAS(?) server in SiteA?

Hi,

Based on my search, if you move a user account to another database within the same Database Availability Group (DAG), the BlackBerry Enterprise Server cannot connect to the user's mailbox.

So, when you fail over the DAG databases, you need to restart the BES Server.

For DAG failover, you need to change the DNS record to CAS server in DR site after you failover to DR site.

Here is a related article for your reference.

http://technet.microsoft.com/en-gb/library/dd351049(v=exchg.150).aspx

Best regards,

Belinda,

(I had originally posted the question with a wrong login).

Correct my if im wrong, but the way i see it, the BES server in DR connects to the CAS in the DR. For all intent and purposes, the BES server shouldn't even care where his mailbox resides given that its the CAS that establishes (or brokers, if you will) the connection to the mailbox. 

Can I not achieve this without DAC mode?

Belinda,

(I had originally posted the question with a wrong login).

Correct me if im wrong, but the way i see it, the BES server in DR connects to the CAS in the DR. For all intent and purposes, the BES server shouldn't even care where his mailbox resides given that its the CAS that establishes (or brokers, if you will) the connection to the mailbox. 

Can I not achieve this without DAC mode?

• Edited by JoeOst 15 hours 47 minutes ago

Belinda,

(I had originally posted the question with a wrong login).

Correct me if im wrong, but the way i see it, the BES server in DR connects to the CAS in the DR. For all intent and purposes, the BES server shouldn't even care where his mailbox resides given that its the CAS that establishes (or brokers, if you will) the connection to the mailbox. 

Can I not achieve this without DAC mode?

• Edited by JoeOst 15 hours 47 minutes ago

Belinda,

(I had originally posted the question with a wrong login).

Correct me if im wrong, but the way i see it, the BES server in DR connects to the CAS in the DR. For all intent and purposes, the BES server shouldn't even care where his mailbox resides given that its the CAS that establishes (or brokers, if you will) the connection to the mailbox. 

Can I not achieve this without DAC mode?

• Edited by JoeOst Monday, December 29, 2014 8:07 PM

Hi,

DAC mode is designed to prevent split brain from occurring. It is recommended to enable DAC when you have each member in a separate data center for DAG.

Here is a related blog for your reference.

http://blogs.technet.com/b/rmilne/archive/2013/12/04/dac-and-should-i-enable-dac-for-a-dag-in-a-single-ad-site.aspx

Best regards,

If BES only sends traffic through CAS (I don't know this, but I'll believe you), and you also recover your namespace as part of your DR, it will work fine.

I'd recommend a single namespace and an active/active DAG. Then you don't have any work to do to recover, though you should still update the namespace to remove site A to improve user experience.

Here's more information about namespaces:

http://blogs.technet.com/b/exchange/archive/2014/02/28/namespace-planning-in-exchange-2013.aspx

"So In the event the prod site (SiteA) goes completely dark, the DAG will failover, and actively mount the database on ExchSrvr2 in SiteB."

Not related to BES in particular, but in this scenario (complete loss or inaccessilbity of SiteA), don't we need to provide for an alternate File Share Witness in SiteB (assuming FSW was originally in SiteA).

Otherwise, the databases would not mount for lack of quorum?

If that is the case, it would be something to integrate in the DR plan (if, of course, you have not already don