Unity 4.x to 5.x and Exchange 2003 to 2007

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Feb 22nd, 2008
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Sorry if this has been covered already, I couldn't find a direct answer.

We're currently running Unity 4.2 attached to our Exchange 2003 server. Now we're getting ready to upgrade to Exchange 2007 so we figure that we need to upgrade Unity first. So we're planning an upgrade to Unity 5.0. I've built a couple of installs in our test system and I see that you can select to connect to an Exchange 2003 OR 2007 mailstore, not both.

Now for our Exchange migration, we're planning to build up a 2007 server and then slowly migrate users over (we have over 1000 at this facility). In my testing, I can see that it's quite simple to switch from Exchange 2003 to 2007, but what will happen during the migration period? If I click it over to 2007, does that mean the users on 2003 won't have Unified messaging available anymore? And if I leave it on 2003 until everyone is migrated over, is that going to mess anything up? I've read that if you have both servers, you need to be sure that Unity creates it's store on the 2007 server. So can I even do that after the install has already been completed with a 2003 server in place? Would it require another upgrade of Unity after 2007 is in place?

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Tommer Catlin Fri, 02/22/2008 - 12:51
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basically, you will need to upgrade to Unity 5.x first. Once you have Unity 5.x hooked into Exchange 2003 and working, then you will need to migrate to Exchange 2007. But once you migrate everyone to Exchange 2007, you will need to change the messaging store integration from 2003 to Exchange 2007.

With using a single Unity server, you can not run both Exchange 2003 AND Exchange 2007. Its one or the other. For what you are trying to do, I would probably try the following.

Install new Unity 5.x server and integrate it to Exchange 2007.

Digital network Unity 4.x and 5.x

As you migrate Exchange users from 2003 to Exchange 2007, migrate them on Unity 4.x to 5.x as well.

Because of your approach you only a few options.

Upgrade to Unity 5.x first, then Migrate ALL exchange users from 2003 to 2007. If you break up the subscribers between 2007 and 2003, the users on 2007 will NOT have voicemail.

Doing this migration is fine. Just puts more pressure on the Exchange Migration team because they have to migrate EVERYONE at one, not just groups.


Install new Unity 5.x server, attach to 2007

Migrate at your leisure. You will need purchase a new MCS server. I dont think you will need a new Unity license because you are essentially migrating, not install a new server. (old server to be decommissioned) The other thing to watch, is to balance your TSP ports to CUCM and routing between servers.


Dave Agro Mon, 02/25/2008 - 08:40
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Thanks for the suggestions tcatlinins!

Does anyone have more information, or a link to documentation about running two Unity servers, more specifically one pointed Exchange 2007 and one pointed to Exchange 2003.

Tommer Catlin Mon, 02/25/2008 - 09:53
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Basically if you have your existing Exchange server running 2003, you install new Exchange 2007. (same Org)

Install your new Unity 5.x server into the same domain. (to exchange 2007)

Refer to the Unity guide on Digital Networking. This basically means the Unity 4.x and 5.x or whatever version you want, can share directories, transfer calls to and from each other, forward, send vmails, etc.

Once they are digitally networked, you can test, slowly migrate subscribers, etc between systems. At one customer we digitally networked 34 Unity servers. (had unity at each site in the US.)


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