Migrating from Exchange 2003 to Exchange 2010

Best Practices in Leapfrogging Exchange 2007 and Going Straight to Exchange 2010

As I covered in my blog post on “The Good, The Bad, and the Ugly in Migrating to Exchange 2010,” I mentioned I would provide more details on the steps needed to migrate from Exchange 2003 to Exchange 2010.  In this post, I’m going to outline the sequence and provide tips, tricks, and best practices to look forward to in the migration process.

Since the migration from Exchange 2003 to Exchange 2010 is similar if not almost identical to the process of migrating from Exchange 2003 to Exchange 2007, if you have already done your design and plan to migrate to Exchange 2007, you’ll find the process to be similar for getting you to Exchange 2010.

The sequence for a migration from Exchange 2003 to Exchange 2010 is as follows:

  1. Bring the Exchange organization to Exchange Native Mode.

  2. Upgrade all Exchange 2003 Servers to Exchange Server 2003 Service Pack 2.

  3. Bring the AD forest and domains to Windows Server 2003 Functional (or higher) levels.

  4. Upgrade at least one Global Catalog domain controller in each AD Site that will house Exchange Server to Windows Server 2003 SP2 or greater.

  5. Prepare a Windows Server 2008 (RTM or R2) x64 edition server for the first Exchange 2010 server.

  6. Install the AD LDIFDE tools on the new Exchange 2010 server (to upgrade the schema).

  7. Install any necessary prerequisites (WWW for CAS server role).

  8. Run setup on the Exchange 2010 server, upgrade the schema, and prepare the forest and domains. (Setup runs all in one step or separate at the command line.)

  9. Install CAS server role servers and configure per 2010 design. Validate functionality.

  10. Transfer OWA, ActiveSync, and Outlook Anywhere traffic to new CAS servers.

  11. Install Hub Transport role and configure per 2010 design.

  12. Transfer inbound and outbound mail traffic to the HT servers.

  13. Install Mailbox servers and configure Databases (DAG if needed).

  14. Create public folder replicas on Exchange 2010 servers using pfmigrate.wsf script, AddReplicatoPFRecursive.ps1,or Exchange 2010 Public Folder tool.

  15. Move mailboxes to Exchange Server 2010 using Move Mailbox Wizard or Powershell.

  16. Rehome the Offline Address Book (OAB) generation server to Exchange Server 2010.

  17. Rehome Public Folder Hierarchy on new Exchange Server 2010 Admin Group.

  18. Transfer all Public Folder Replicas to Exchange Server 2010 Public folder store(s).

  19. Delete Public and Private Information Stores from Exchange 2003 server(s).

  20. Delete Routing Group Connectors to Exchange Server 2003.

  21. Delete Recipient Update Service agreements using ADSIEdit.

  22. Uninstall all Exchange 2003 servers.

Key to note in the migration process from Exchange 2003 to Exchange 2010 is that many concepts go away such as the concept of routing groups and administrative groups.  Routing groups and Administrative groups were legacy from the days prior to Active Directory where Exchange 5.5 or earlier needed to have configuration settings to allow for the creation of administrators and the routing of mail.  These concepts were brought forward in Exchange 2000 and continued with Exchange 2003, however with Exchange 2007, Microsoft did away with these concepts and began leveraging the administrative roles and the Sites and Services routing roles built in to Active Directory.  With the elimination of administrative groups and routing groups, a major tip is to make sure your Active Directory is setup and working properly.  The requirement to be in Active Directory 2003 native mode is that instead of distribution lists in Exchange, Exchange 2010 uses Universal Groups in Active Directory.  Where in the past we used to create global security groups in Active Directory, now you want any group that’ll be mail-enabled for Exchange to be a universal group.  And for the proper routing or mail, make sure that your Active Directory Sites and Services is setup properly regarding subnets and site links between subnets so that mail between different Exchange servers will properly follow the shortest or fastest path designated in AD Sites and Services.

Also important to note is that all roles (bridgehead, frontend, and backend) in Exchange 2003 need to remain until all users are migrated to Exchange 2010.  Exchange 2010 CAS, Hub Transport, and Mailbox servers are not backwards compatible with Exchange 2003, so in order for a user to access Outlook Web Access on Exchange 2003, they need to still hit the Exchange 2003 frontend and access their mailbox on the Exchange 2003 backend server.  After their mailbox is migrated to Exchange 2010, then the user will hit the Exchange 2010 CAS server and access their mailbox on the Exchange 2010 Mailbox server.  Because Exchange 2010 has a proxy service on the CAS server, your external URL for OWA can point to the Exchange 2010 CAS server and if the user’s mailbox is still on Exchange 2003, the CAS/2010 server will automatically redirect the client connection to the FE/2003 server for OWA.

Lastly, after moving mailboxes off of Exchange 2003 to Exchange 2010, leave the Exchange 2003 infrastructure in place for a couple (2) weeks.  By leaving the old Exchange 2003 server(s) in place, when an Outlook client tries to connect to the old Exchange 2003 server for its mail, the old Exchange 2003 server will notify the Outlook client software that the user’s mail has been moved to the Exchange 2010 server and will automatically update the user’s Outlook profile with the new destination server information.  Thereafter, when the Outlook client is launched, Outlook will access the user’s mailbox on the new Exchange 2010 server.  By leaving the old Exchange 2003 infrastructure in place for a couple weeks, pretty much all of your users will launch Outlook to have the profile automatically changed thus requiring no client system intervention during the migration process.  The only users you will likely need to manually reset their Outlook profile are users who are on extended leave and had not accessed their Outlook mail during the 2 week time that you had the Exchange 2003 environment still in place.

Hopefully these steps are helping in providing you guidance in your migration from Exchange 2003 to Exchange 2010.  I cover the migration process in much more detail (including specific steps and step by step processes for cutting over Frontend to CAS, Bridgehead to Hub Transport, Backend to Mailbox server roles) in my book “Exchange 2010 Unleashed” from Sams Publishing.  The book was written from 2-yrs of early adopter experience working with Exchange 2010 and will hopefully provide more detailed guidance on the migration process from Exchange 2003 to Exchange 2010.

My next post will be on the migration process from Exchange 2007 to Exchange 2010 for those who are already on Exchange 2007.


Copyright © 2009 IDG Communications, Inc.

The 10 most powerful companies in enterprise networking 2022