I have a client that wishes to migrate about 20 users over to our Zimbra server. Good news of course but I'm stuck trying to find the best way to deal with their concerns.
1) Minimal/0 downtime - they're 24/7 busy so any downtime causes problems
2) Importing Outlook PSTs. Each user is currently using outlook via a traditional POP account on their hosting server. Each user has ~1-2GB of mail. Their connection allows uploading of ~2-4Mbps so each user's import is going to take quite some time.
So what I'm wondering is if there is some way to migrate users one-by-one. I'm guessing I could use the external POP mail checking tool to do this, but the problem I see there is that once a user is migrated to Zimbra, then they go to send outgoing mail to other users on the domain - Zimbra would route the mail to their "new" account instead of the old POP account.
How do we handle this?