Consider a small-medium business' deployment of Exchange 2003. The question is around migrating to Exchange 2010. Here's a bit about the landscape:

  • Current state is 50-100 users/mailboxes with the majority using Outlook 2007
  • OWA enabled
  • desktop users are NOT running in Cached Exchange Mode
  • laptops users ARE running in Cached Exchange Mode
  • a single Exchange server with modest or reasonable specs for the day (3 GHz, multi-core, 4 GB, Windows 2003 32-bit)


  • What are your suggestions for the administration team regarding the upgrade path/steps from Exchange 2003 to 2010?

  • Considering the requirement of a 64-bit OS, consider a new separate machine as ready to go with Windows 2008. Have I missed any details?

  • Where might virtualization help in this project?

Any lessons learned in previous upgrades (2007 or 2010) would be appreciated!

  • This should be community wiki... – GregD Dec 4 '09 at 16:46
  • I don't have anything technical to add as the other answers are excellent, however be aware that with an Exchange 2010 CAL, it doesn't not provide the equivalent license to run Outlook, unlike Exchange 2003 CALs. If you do not have other copies of Outlook, this cost should be considered. – Jeff Miles May 4 '10 at 21:26

It sounds like a piece of cake, to be honest. A single server, single physical location scenario like you're describing is the easiest migration to perform. Follow the guidelines from Microsoft and you'll be well on the way to success. You're basically talking about a "Move Mailbox" migration, with zero visibility to the users.

Your Exchange 2003 install should already be at Service Pack 2. That's all that's really necessary there.

Exchange 2010 has the feel of a minor version upgrade from Exchange 2007 (what w/ a lack of major architectural changes like there were between 2003 and 2007), and the migrations I've done from 2003 to 2007 have been very smooth anyway. I expect that 2003 to 2010 migrations will be equally smooth (though I haven't had occasion to do any yet... anybody game?).

You're saying the right things re: getting a new server computer to host Exchange 2010. Be sure you provision your storage per Microsoft best practices (separate spindles for ESE transaction logs and databases, tuned for sequential access for the former, and random access for the latter).

I have seen some hiccups in Exchange 2003 to 2007 migrations when users have their mailboxes open, while in Cached Exchange Mode, during the migration. It's supposed to be possible to move a user's mailbox while they're using Outlook, but I wouldn't chance it-- I'd be sure that they aren't using Outlook while moving the mailboxes.

If you're going to cut everyone over at once, changing your firewall rules that forward OWA access from the Internet to the new Exchange Server computer isn't a big deal. If you plan to coexist mailboxes on both servers for a time, then you're going to need to worry about users accessing the right instance of OWA to get to their mail, depending on whether their mailbox has moved or not. (That's a good argument for cutting over all the users at once during a scheduled downtime interval.)

I don't know that virtualization will "help" in the sense that the migration is going to be the same whether you're migrating onto bare metal or a virtualized machine. Exchange 2010 is more friendly than prior Exchange versions with respect to IO needs, so running in a virtualized environment (where you incur some amount of IO overhead due to being virtualized) is going to less of an impact as compared to prior Exchange versions.

If you're hosting any Exchange-integrated antivirus are you ready to go with a license for an Exchange 2010-capable version?

Is your backup management software ready to support Exchange 2010?

You may want to read up on Exchange Autodiscovery. It can have ramifications for your SSL certificate and DNS infrastructure, assuming you don't want to get little annoying warnings from Outlook. Have a look at these for some good background (the second refers to Exchange 2007, but it hasn't change dramatically in Exchange 2010).


I had just performed an exchange 2003 to exchange 2010 migration. First off, this went flawless! I was so happy with the outcome. As many of you know, Exchange 2010 requires 64 bit OS. THEREFORE, I started the projected by creating a new 64-bit Windows 2008 enterprise server and a new windows 2008 64 bit enterprise domain controller in an existing 2003 active directory environment.

First, let me say that you have to run adprep off the 2008 cd on your DC that holds your fsmo roles.

I installed exchange 2010 and brought up a new BES 5.0.2 server as I thought this would be an excellent time to refresh corporate blackberry users.

I love this version of exchange! I was running co-existence mode until the migration was complete and then I uninstalled exchange 2003 from my environment and retired that old clunky exchange server. Let me say that despite the noise about making your client access and mailbox role a VM. I had no issue doing this, as I am a huge VMware and virtualization fan. I have had no issue with my cas, hub, and mailbox roles all in one VM with zero performance issues.

One thing I do not like is that by design store.exe is now a memory hog! However, there are parameters that you can use in adsiedit.msc where you can limit the memory usage of store.exe that work great!

All in all the only complaint I got was from the helpdesk, as they cannot install Exchange management tools on their desktops because they run 32 bit OS. I told them to upgrade their desktop OS to 64 bit so they can run the tools. I know they make some third party management tools that allow your helpdesk to still perform common exchange tasks but I am NOT a big third party fan.

If anyone has any questions about more details about my migration from exchange 2003 to 2010 I will be more than happy to answer them. In addition, when you plan your exchange 2010 rollout one big thing to remember here is give yourself plenty of space for the info store lun as exchange 2010 does NOT like to have less than 2 GB free space of the store lun or luns. If it goes below 2 GB mail will stop flowing and will not flow again until you free up some space.


We are considering the same upgrade here and I found this document which seems quite detailed and straightforward. http://www.simple-talk.com/sysadmin/exchange/upgrade-exchange-2003-to-exchange-2010/

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