I have two new Exchange servers (PROD1 and DR1) that I recently updated to CU8 in preparation for going into production.  After reboots, I noticed that I had a warning on the "Server Manager" window.

PROD1 lists itself, DR1, and DAG1 as servers though it marks DAG1 as not accessible.

DR1 lists only itself and PROD1.  It does not list DAG1.

PROD1 is generating a ton of failover cluster errors (1205, 1254, 1069, 1044) while DR1 is clean.

In the Failover Cluster Manager of each server, the object of DAG1 is listed as "Offline".  It has two IPs - one for each of the Exchange servers' subnets (this is where I think I screwed up).  The IP for PROD1's subnet is 10.2.8.131 and is "Failed" and the IP of DR1 is 10.4.8.131 and is "Offline".  The IP of PROD1 is 10.2.8.132 and DR1 is 10.4.8.132.

Attempts to bring the cluster object online fail "due to the failure of one or more provider resources".

The instructions I followed to set up the DAG did not mention the need for multiple NICs.  I now think this is incorrect and would be willing to use separate subnets and NICs for the DAG if necessary.  (I could use 10.2.12.X and 10.4.12.X instead.)

I am currently still able to fail the database copy between DR1 and PROD1 without any problems.

Hi jkm,

Thank you for your question.

Could you post more details which is about Event ID to ibsexc@microsoft.com for our troubleshooting?

Owing to cluster offline, DAG will go offline. Frist we should make sure cluster is online.

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim

Hi Jim,

Are you asking for more details about the errors generating on PROD1?

As mentioned, the DAG still seems to be online since I am still able to make either server the primary for the database.

Hi Jkm,

As you said :PROD1 is generating a ton of failover cluster errors (1205, 1254, 1069, 1044) while DR1 is clean.

I suggest you post failover cluster errors to ibsexc@microsoft.com for our troubleshooting.

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim

You don't need multiple NIC's for Dag members. The Preferred Architecture even talks about removing redundant NIC's.

Can you move the cluster group owner to DR1?