Exchange 2010 - Dual site DAG

Hi all,

We are currently looking at replicating the current Exchange database to another datacenter, so we can run side by side.

Currently I have

Site 1
2x DCs
2x HUB/CAS Servers
2x Mailbox Servers (In a DAG)

Site 2
2x DCs
2x HUB/CAS Servers
2x Mailbox Servers (joined to the original DAG)

Site 1 - Network Config
Replication -

Site 2 - Network Config
Replication -

I have configured the replication networks with static routes so they can route to eachother between datacenters.

Since I have joined all these Mailbox servers to the DAG that exists in Site 1. I guess this is now a stretched DAG?

Under the EMC > Database Availability Groups > Networks

When I added the servers from the 2nd site, into the DAG.
I have 4 networks.

MAPI Datacenter 1
MAPI Datacenter 2
Replication Datacenter 1
Replication Datacenter 2

I have now consolidated these into

and the subnets for both the replication networks are in Replication and both MAPI networks are in the network named MAPI.

Is this correct?

I've read a bunch of exchange 2010 setup docs, but unable to find any good 'these are the 5 steps u need to do, to get a dag setup in a 2nd datacenter'.

When I try to add a copy of a database to a node in the other datacenter, I get this error:

A source-side operation failed. Error An error occurred while performing the seed operation. Error: Failed to open a log truncation context to source server 'Exch02.domain.local'. Hresult: 0x5. Error: Callback
. [Database: Archive, Server: Exch03.domain.local]
    + CategoryInfo          : InvalidOperation: (:) [Update-MailboxDatabaseCopy], SeedInProgressException
    + FullyQualifiedErrorId : EC3D0B4D,Microsoft.Exchange.Management.SystemConfigurationTasks.UpdateDatabaseCopy

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Do I need another FSW, as I intend to implement DAC too.

When I try to add an additional IP to the DAG for the other datacenter network, it get an error stating that the FSW does not have the Exchange Trusted Subsystem added to the local admins on that server, even tho it is.

Sorry for all the questions!
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It sounds like you've done everything correctly. Don't worry about the FSW error - that is a known bug and it will give you that error message every time you run the "Set-DatabaseAvailabilityGroup" command. If you want to be sure that the FSW is configured correctly, run the following command:


I would also create an Alternate File Share Witness (in the second 2nd site) and set those settings on the DAG. This will speed up the recovery process when you need to do a complete site failover.

Make sure that you have the exact same storage path in the target node as you do on the source servers i.e. if your database sits in D:\Data\DB1\DB1.edb, you need to have a 'D' drive on the target server (as the paths have to match on all DAG nodes).

For the database copy that you attempted to create, check to see the status by running the following command:
Get-MailboxDatabaseCopyStatus DBNAME\DAGNODENAME

If the copy is suspended you can try to force an update
Update-MailboxDatabaseCopy DBNAME\DAGNODENAME

I think the syntax of these commands are correct but am not in front of a machine to test them.

There are other things you should do as well in relation to Client Access - i.e. creating a CAS array and configuring the databases to use the CAS array. If you need more assistance with that please ask.

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MarkMichaelAuthor Commented:
Thanks for the help!

The logs/database drives are set equally across the sites, using E: and F: on all servers.

This is the status of the server with the failed copy status which I cant get going.

Name              : Archive\EXCH03
Status            : FailedAndSuspended
CopyQueueLength   : 36339
ContentIndexState : Failed


Server          Check                      Result     Error
------          -----                      ------     -----
EXCH03        ClusterService             Passed
EXCH03        ReplayService              Passed
EXCH03        ActiveManager              Passed
EXCH03        TasksRpcListener           Passed
EXCH03        TcpListener                Passed
EXCH03        DagMembersUp               Passed
EXCH03        ClusterNetwork             *FAILED*   Failures:... (Backup NIC related - as these havent been enabled)
EXCH03        QuorumGroup                *FAILED*   Quorum resource 'Cluster Group' is not online on server 'EXCH02'. Database availability group 'DAG01' might not be reachable or may have lost redundancy. Error:
        IPv4 Static Address 2 (Cluster Group): Offline
        Cluster Name: Offline is offline. Please verify that the Cluster service is running on the server.

[i]Possibly related to the new DAG Address I've allocated which gave errors? [/i]

EXCH03        FileShareQuorum            Passed
EXCH03        DBCopySuspended            *FAILED*   Continuous Replication for Database 'Archive\EXCH03' is in a 'FailedAndSuspended' state on machine 'EXCH03'. The reason it is suspended is: A source-side operation failed. Error An error occurred while performing the seed operation. Error: Failed to open a log truncation context to source server 'EXCH02.domain.local'. Hresult: 0x5. Error: Callback

EXCH03        DBCopyFailed               Passed
EXCH03        DBInitializing             Passed
EXCH03        DBDisconnected             Passed
EXCH03        DBLogCopyKeepingUp         Passed
EXCH03        DBLogReplayKeepingUp       Passed

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I'm comfortable with creating a new CAS array for this datacenter, I don't think I will have a problem with that.

I am still simply having issues with the 2 main points:

1. trying to update the databasecopy is still failing when I run the update command.
2. The IP address in the 2nd datacenter is not pingable, after it was added. Should it be?

Thanks again!
MarkMichaelAuthor Commented:
Active Directory seems to have been my problem!

It looks like we had some bad replication occurring and this stopped Exchange from updating mailbox copies.

Since that's fixed, its allowing to copy the databases.

I've also tried to add an alternate FSW, however there is nothing getting created at c:\filesharewitness\dag\ directory on that particular server. Is this normal?
I still cant bring the IP address online, in the 2nd datacenter for the DAG. Have you encountered any problems with this?

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My apologies, I forgot that your DAG has only two nodes. During activation in the second site when your primary site is down, you won't need a FSW as you'll have a majority with the single node.

In relation to the other IP address, you can only have one of the DAG IP's online at any one time. If the IP in the primary site is active, the other one will be offline. If you shut down the DAG node in the primary site the other node should bring that second DAG IP online (and the primary DAG IP will be offline). This is normal and correct.
Just to clarify, if you run the Test-ReplicationHealth command now you should not get any errors.
MarkMichaelAuthor Commented:

I actually have 4 mailbox servers in this DAG.
Does this FSW bit remain the same?

I've ran the test-replication health and all but 1 has passed. The one that has failed is about our backup network not configured yet. Which is totally fine!
I'll give you all the points in a few moments.

Thanks again for your help!

I'm going to build a new question about the CAS array (that I thought I was comfortable with, however, the more I think about it, the more questions i seem to have:))

Ok - if there are four servers in the DAG (2 in each site), then you will need to have the alternate FSW in the second site. You will only need it in the event of failover though. If it's already created then it's one less step you have to do during the failover process.
MarkMichaelAuthor Commented:
I have created it, but there are no files in the destination directory. Will this be created when I attempt a failover?

FYI, this site is being created as we need to move out of our current datacenter to a new one.

We will be failing over to this setup and then using it as the primary site. Removing Exchange from the other active directory site.

(In the long run, we will then be building a new site in a 3rd datacenter, so we can again have 2 sites for Exchange.)
Can you see any problems with that?

Thanks again.

Yes- when you attempt a failover, the necessary files will be created. Don't forget to make sure the Exchange Trusted Subsystem group is in the local Administrators group on that server.

There won't be any problems with what you're planning. In fact, if you remove the servers gracefully you should be able to do it without affecting users (albeit, minor disruption only while databases switch over...)
MarkMichaelAuthor Commented:
Lovely, that's the plan!

Thank you again. You may want to watch out for my cas array question that I'll add tomorrow, since you're very knowledgeable and helpful. :)
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