Often the two migrations I’ll bet people look at at Hybrid for Exchange 2010 and 2013 or A Cutover (for everything else)
The REASON I think Hybrid is looked at more often is simply that if you add in one Exchange 2010 server into your current Exchange 2007 infrastructure, you can reap the benefits of a Hybrid as well.
The cutover is probably quite popular because the technical knowledge required for a cutover is very low. You literally Export the mailboxes from workstations and Import them back into the cloud. It’s Time intensive depending upon the size of your data store but the most technically complex part is changing the MX records about.
But there is a 3rd option that sometimes gets ignore that is perfect for Exchange 2003 and Exchange 2007 systems that has very little Risk in it’s setup or implementation, that is the Staged migration.
In the Staged Migration the flow works like this
- Point Office 365 to your External URL for OWA
- Give it a list of Mailboxes
- Sync those mailboxes to Office 365
- Flip the ID’s from Mailbox on Prem to Mail Enabled
- Repeat until all mail is done
This scenario requires some permissions and is slightly more technically challeneged than a straight cutover but it offers up some options you may not have realized.
- Mail from users in Office 365 to on Prem continues to flow back and forth
- You don’t need to touch the MX records until you absolutely have to
- Email addresses Migrate up and do not need to be re-created manually
There are some things it does not migrate (like mailbox permissions) but it does allow you to migrate users in blocks and avoids all that nasty “We have to move everybody over this weekend” nonsense.
… The best part? You can automate 95% of this with Windows PowerShell so you don’t need to stay up all night watching email Import.