Note that this is meant to onboard users to Office 365 however, not meant for long term synchronization. It will only synchronize one way; from your IMAP source to Exchange Online. If you're interested in bi-directional sync, there are some third party vendors who have solutions for that.
Hope this helps, and please reply if you're looking for more.
Thank you for clarifying my terminology.. I've got to have the right if I'm going to explain myself correctly. 8-) I've read that page you referenced before.
I am interested in a somewhat long term synchronization.. however my users will not have access to the O365 account until after a final synchronization, so a one way sync will work just fine... as long as it supports deletes. (i.e. initial sync from IMAP to O365 is complete, user deletes messages from IMAP account, incremental sync happens -- the messages that were deleted from the source IMAP are now also deleted on the destination O365).
My use case is 1300 users with a total of about 5TB of email in the on-prem IMAP server (Zimbra).
I've looked at other 3rd party tools, but the O365 ingest rate is just not high enough to consider a weekend cutover event.
And the 3rd party tools I've looked at do not support the deletes referenced above.
If the IMAP sync will actually keep the O365 in sync with the IMAP, then I don't really care if it takes 2 days, 2 weeks, or even a month to get all 1300 users in.
As long as I can do a final sync over a weekend and then switch off my on prem Zimba.
I've been using "Get-MigrationUserStatistics -Identity firstname.lastname@example.org -IncludeReport | FL" to follow the process, but more insight here would be helpful.
I will take any and all information help you can provide.
I get what you're trying to do, and you're on the right track with your powershell commandlets to track the status. With your migration plan though, I would cut over as soon as possible after your mailboxes are synced to avoid errors. The longer you keep them in sync with an IMAP migration, the more likelihood of errors.