Exchange 2010 SP3 DAG Help

Posted on 2013-06-05
Last Modified: 2013-06-05
Hi All

We started off with 1 site all with 2012 servers and Exchange 2010 SP3. This site is in Production and Exchange is fully configured and working. Partial DAG setup was done before second site was up for some reason (not by me).

We have now added a DR site again with 2012 servers and I want to configure a DAG but have faced some issues. Exchange has been installed and updated to same patch level, and thats it so far.

Here are the networks:

Production site:
Exchange Replication:

DR site:
Exchange Replication:

Note the Replication Networks are tied down to single IP's for other reasons but I dont believe this should cause any issues.

On the Production Exchange Server I first removed all the existing DAG and this is where I faced my first problem. After removing the only member server I went to remove the DAG itself (via EMS) and it completed, although with an error that the Exchange Trusted Subsystem was not added as Local Admin of the Witness Server (it really wasn't).

We ended up in a state where one server showed the DAG had been deleted and one showed it in the GUI still, but unable to do anything with it.

I cant remember exactly what was done but eventually we got it out of both GUI's.

Started to create a new one from scratch. The DAG IP was set to 192.168.61.X. When I added the member servers in (both), it threw up an error (sorry didnt copy it down) that there was an issue DR Site Exchange server and something to do with the DAG IP. It listed as failed but in the GUI it displayed both servers as members.

Again, was unable to do anything in the GUI to remove it. Ended up able to remove it using the -configurationonly switch via EMS.

So now we are back to a blank slate.

I just tried again this morning, and when setting up the DAG it immediately comes up with an error:

Summary: 1 item(s). 0 succeeded, 1 failed.
Elapsed time: 00:00:00


A computer account named 'Company-DAG' already exists and is enabled. The account must be disabled in order to be used by the database availability group.
Click here for help...

The operation wasn't successful because an error was encountered. You may find more details in log file "C:\ExchangeSetupLogs\DagTasks\dagtask_2013-06-05_08-43-14.985_new-databaseavailabiltygroup.log".

Exchange Management Shell command attempted:
New-DatabaseAvailabilityGroup -Name 'Company-DAG' -WitnessServer '' -WitnessDirectory 'C:\Witness'

Elapsed Time: 00:00:00

I was going to reboot the servers tonight but I have a feeling this will not solve it and that there is remnants of the old DAG's in there somewhere.

What should I do?
Question by:bikerhong
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LVL 63

Expert Comment

by:Simon Butler (Sembee)
ID: 39221539
Have you removed the computer object from ADUC? If not then that is the reason for the error you are seeing. There is always a chance that you still have some reminants in the cluster manager as well, so check there.
Rebooting isn't going to help because this isn't really an issue that is cleared by rebooting.


Author Comment

ID: 39221552
Thanks Simon.

I have deleted the computer object now.

In Cluster Manager I can see "" which is down and has a sub-item of Cluster Events.

If I right click it all I get is:

Validate Configuration
View Validation Report
Connect to Cluster (greyed out)
Start Cluster
Force Cluster Start
Close Connection

How do I get rid of it completely?
LVL 63

Accepted Solution

Simon Butler (Sembee) earned 500 total points
ID: 39221891
You will probably have to do it with the command line using remote-cluster command.

I haven't got an Exchange 2013/Windows 2012 platform up at the moment to confirm exactly.

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If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.


Author Comment

ID: 39222053
Thanks Simon, that did the trick.

Now, I have created the actual DAG with no problems.

When I try to add the 2 member servers I get the error: You must provide a value for this property.

A google search led me to this link about pre-staging the CNO.

Is this right, if so what is the CNO? I'm a bit confused as to what I need to do.

Author Comment

ID: 39222090
Never mind I think I sorted it.

On adding the member servers I got this:

Summary: 2 item(s). 2 succeeded, 0 failed.
Elapsed time: 00:01:06


Exchange Management Shell command completed:
Add-DatabaseAvailabilityGroupServer -MailboxServer 'BERLIN' -Identity 'Company-DAG'

Elapsed Time: 00:00:51


Network name 'Company-DAG' is not online. Please check that the IP address configuration for the database availability group is correct.

Network name 'Company-DAG' is not online. Please check that the IP address configuration for the database availability group is correct.

Exchange Management Shell command completed:
Add-DatabaseAvailabilityGroupServer -MailboxServer 'OSLO' -Identity 'Company-DAG'

Elapsed Time: 00:00:14


Right now the production server lists the DAG, along with both the member servers etc, looks ok.

However on the other server, DAG section is completely empty.

Do I need to wait for some kind of replication or has something else gone wrong!!

Author Comment

ID: 39222117
Ah - now there is an error.

If I right click the DAG and select Properties a pop up error comes up:

A server-side administrative operation has failed. GetDagNetworkConfig failed on the server. The NetworkManager has not yet been initialized. Check the event logs...


Author Comment

ID: 39222143

Forced replication and it fixed itself.

Author Comment

ID: 39222247
OK, sorry for the continuous updates. I am now stuck on the following:

Exchange Management Console shows everything is UP on both servers, but the Cluster Resource Manager still reports the cluster name as DOWN (unable to bring up manually).

The DAG Networking in EMC shows everything is UP, however:

2 x LAN Networks - OK
2 x Replication Networks - they are both showing with IPv6 (we not have an IPv6 routable network). Due to this also I am unable to determine which network belongs to each site as both Replication networks shows each side's IPv6 address.

Any attempt to manually bring online the Cluster Name gives the error: An error occurred while attempting to bring the resource "Cluster Name" online. Error Code 0x80071736.

How should I proceed?
LVL 63

Expert Comment

by:Simon Butler (Sembee)
ID: 39222488
You shouldn't do anything with the cluster in the cluster management tool. Do everything with Exchange. Sounds like you may have replication issues, so it might just be a matter of waiting.


Author Comment

ID: 39222501
I dont know if it wqas another replication timing issue but all I know is, after attempting to force the replication networks to pick ip the IPv4 address by disabling IPv6 and rebooting (didnt work) - when I reverted it, it all pinged to life.

Thank you Simon  for your help.

I have another question open now on drive letters and database copies ;)

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