Tips and Tricks for Migrating to Exchange Online, presented at the Office 365 UK User Group Birmingham, 12th February 2014

1. Tips and Tricks for
Migrating to Exchange
Online
Steve Goodman
12th February 2014

2. Who am I?
• Dad and Husband
• Infrastructure Consultant at Ciber UK
• Exchange VTSP at Microsoft
• Exchange Server MVP
• Host of The UC Architects Podcast
• Blogger, PowerShell Scripter, Author

3. What am I talking about this evening?
• What to think about before you think about migrating
email
• Options for migrating email to Office 365
• Top tips for each method of migration

4. Before you begin!

5. What to consider before you set things up
• Is your Active Directory structure an easy fit
for Office 365?
• Are you prepared (or able) to update User
details?
• Do you have an understanding of your
Exchange environment and patch levels?

6. What to consider before you set things up
• Do you know what clients and apps are in
use, and can you update them?
• What resource do you have available to
support your migration?
• What are your deadlines to migrate?

7. Migration Approaches

8. Cutover Migration
• Migrates ALL mailboxes in one go
• Suitable for Exchange 2003, 2007, 2010 and
2013
• Limited to a maximum of 2000 mailboxes
• Uses Outlook Anywhere to copy mailboxes

9. Staged Migrations
• Migrates mailboxes in batches
• Suitable for Exchange 2003 and 2007
• Uses Outlook Anywhere to copy mailboxes

10. What is a Hybrid Migration?
• Link Exchange to Exchange Online
• Requires Exchange 2010 or 2013
• Move mailboxes, not copy them - highest
fidelity of moves
• Move to or from the Cloud

11. Other Migration Methods?
• IMAP Migration
• Wide range of source systems, low fidelity
• PST Migration
• Export as PST, Import using PST Capture Tool, flexible but
crude
• Third-Party Tools fill the gaps
• Cloud-based tools (e.g. BitTitan MigrationWiz)
• On-Premise tools (Quest, BinaryTree)

12. Top Tips and Tricks

13. Cutover and Staged Migration Tips
• Make sure Outlook Anywhere is enabled, available externally
and you have a valid third party certificate
• Test using the Remote Connectivity Analyser
• The Mailbox is copied so needs profile reconfiguration
• Can involve visiting desktops 
• Do you have mailboxes hidden from the GAL?
• Ensure mailboxes you are migrating are visible.

14. Cutover and Staged Migration Tips
• Mailbox permissions aren’t copied and need to be re-applied
• New Collect-MailboxPermissions.ps1 on it’s way to www.stevieg.org
• After migration is completed switch off Internal AutoDiscover
• Set-ClientAccessServer <ServerName> -AutoDiscoverInternalURI:$null

15. Cutover Migration Tips
• Get Active Directory and DirSync ready for after your migration
• You can sync user details and passwords as you cutover
• If you use DirSync think about how you’ll manage Exchange
• Are you leaving DirSync in place?
• Lower DNS TTLs to enable a quick switchover

16. Staged Migration Tips
• Perform adequate testing before moving real users
• Failed migrations can leave users in a half-migrated state
• Move People and Shared Mailboxes together where you can
• If you struggle to do this, a Staged Migration might not be for you
• Convert Mailboxes to MailUsers after each migration batch
• http://community.office365.com/en-us/wikis/exchange/845.aspx

17. Hybrid Migration Tips
• Make sure Exchange is published to the Internet optimally
• Correct Certs, AutoDiscover, No Pre-Auth for Hybrid-related URL Paths
• Exchange 2010 includes all you need for a hybrid migration
• You don’t need a “Hybrid Server”, but you do need a minimum of SP3
• Exchange 2013 is the best choice for a long coexistence
• Easier setup, free hybrid license and target for new Hybrid features

18. Hybrid Migration Tips
• Clean up any cross-forest sidHistory issues before migrating
• sidHistory isn’t migrated and can break permissions
• If you can, remove Public Folders rather than migrate them
• No compelling co-existence story and added hassle
• Use “Suspend When Ready to Complete” to perform quick
switches of mailboxes
• Performs a full sync of mailboxes, allowing you to perform a final sync
then switch in minutes

19. Tips for any migration method
• Export oversize messages first
• Export messages over 34MB to PST and / or encourage users to clean
up mailboxes
• Third Party tools can make complex migrations easy
• Cloud-based tools like MigrationWiz save a lot of time and can provide
flexibility Microsoft tools cannot
• Think about the user experience
• A simple server-side setup might mean a complex desk-side migration

20. Summary

21. Summary
• Understanding your environment before you begin is critical to
success
• Microsoft provide Cutover, Staged, Hybrid and IMAP migration
methods
• Additional options include PST and 3rd party tools
• Hybrid migrations require a little more setup, but are worth the
effort

22. Any questions?