We have two Exchange 2013 cu3 Servers on Server 2012.  We want to migrate to Exchange 2013sp1 (cu7) and Server 2012r2.  The servers are in a DAG at this time, and we would like to add a Server with the Edge Transport Role.  I know that I will need to bring in New r2 servers, and that I will need to disable the DAG because the servers will be different OSs.  But what would be the best and most time efficient steps to get through this migration of updating to the latest Exchange and the operating system.  Thank you for any assistance with this. 

Hi Dfoli,

Exchange 2013 SP1 includes schema changes. Hence first install is going to take sometime.

1. Setup the new R2 servers with Exchagne SP1 CU7 in the existing environment.

2. Put them in DAG2(new), create DBs with copies prior to moving mailboxes.

3. Move mailboxes out of old server to new server databases

4. On old server Remove exchange, upgrade the OS, re-install Exchange (Make sure you are moving all mailboxes out including the Arbritation mailboxes)

5. Bring back the mailboxes, if you like to the old servers with new exchange.

NOTE:- Edge server needs to be on a seperate server(can't have CAS or MBX role), preferably standalone (not domain joined) as earlier releases.

Something not quite relevant, but worth mentioning below:

You can safely move a database between servers running Exchange 2010 SP1, SP2 or SP3. Even though you can move databases between mailbox servers running different service pack levels, you should complete the upgrade of all DAG members to the same service pack level without too much delay. We recommend that you minimize the amount of time you have your DAG members running different service pack levels.

Nice article:

Why you absolutely cannot upgrade Windows on an Exchange server

Satyajit,

Thank you for your reply.  Is there anything that I should be watching for, on the old servers, when I stand up the first new server?  Also, once I move the DBs to the new servers and remove Exchange from the old servers can I just get rid of the old servers?  Thank you again.

DFoli

Hi Dfoli,

Make sure you are moving all mailboxes from the old server DBs including the arbitation mailboxes.

Keep the DBs on old server dismounted for sometime and observe for any unsual issues. If all fine,delete the DBs, shutdown the server for sometime and then observe.

If all fine,boot up the old server, uninstall the exchange component, and disconnect from network keep it aside if you dont want it again(Format it better, so that you can reuse if you want and hope you dont want someone else snooping in your exchange logs etc later down the line).

You can delete the AD computer object as well from Sites and Services\ADUC etc. If you plan not to have it anymore.

Satyajit,

When I do the first install will the schema changes affect the existing Exchange Servers?

Hi D. Foli,

Schema changes are applied on the the AD server hence, you should give sometime for the changes to reflect across all AD servers(replication to complete-maybe an hour or so). And yes it will be visible to all Exchange servers talking to the AD servers (Not to worry anything here, as your existing servers should continue to run just fine)