**UPDATED on January 6, 2012**
Thanks to both user comments and NetApp themselves, we have determined that there is an easier way to add disks to members of a DAG without removing them from the DAG. You can simply stop the Windows Clustering service (run the command “net stop ClusSvc” from the command line). Obviously you should move any active mailbox databases on this DAG member to another DAG member before doing this, as stopping the clustering service will cause the databases to dismount and move on their own. From there, you should be able to add the disk’s, start the clustering service, and your DAG member will automatically return to a normal operating mode, participating in the DAG.
Thanks to all who sent this in!!
I recently ran into an issue where I was unable to add an RMD LUN to a Windows Guest running on VMWare vSphere. Here is my setup.
I had a Windows 2008 R2 guest that was running Exchange Server 2010 SP1. The guest was a Mailbox server that was a member of a Database Availability Group. I was attaching the LUN’s to iSCSI RDM’s that were based on a NetApp FAS 3140 running ONTAP 7.3.2. The guest was running version 6.3 of Snapdrive.
The guest had 12 iSCSI RDM’s working properly for month’s, but the issue arose when I tried to add more. I would be able to select the volume, create the LUN, size, the mounting location of the LUN. The issue was when in Snapdrive I was presented with where to store the RDM file for the VM. See the screen below:
The problem was the console starting freezing up, and generally not responding.
After several minutes, I eventually received an error stating there was an “error in fetching number of vmfs datastores”
I tried all the basic’s, re-installing Snapdrive, upgrading to Snapdrive 6.3 PP1, rebooting the host, stopping and starting the service.
Turns out there is a bug in Snapdrive that causes the error above, when the Guest is a member of a Windows Cluster. Since all DAG members utilize Windows Clustering, this applied to me. The resolution was easy.
I moved all the databases off of the server in question. Then, in Exchange Management Tools, I went to Organization Config->Mailbox and selected the Database Availability Tab. Right click your dag and select Manage Database Availability Group Membership:
Right click the server in question, select Delete and then the manage button. This will remove the server from the DAG.
[This will not cause any issue with the existing databases as we’ll see below]
Now, go back into Snapdrive and add your LUN’s, all should be working now.
After your done, add the server back to the Database Availability group, almost the same way you removed it, this time select Add, and then select the previously removed server and add it back.
Next, for each MailboxDatabase that the server has copies of, run this command in the Exchange Management Shell:
Add-MailboxDatabaseCopy –Identity MB01 –MailboxServer NYDAGNODE1
Or in the EMC, go to Organizational Configuration->Mailbox and right click each Mailbox Database and select Add Database Copy. Then select your server.
Since the server still has copies of the Mailbox Databases, it will start to resynchronize with the DAG, and bring itself up to date. That way you won’t need to reseed your entire DB which can take some time.
Hope someone finds this useful!