Transferring maildir emails to another server

Question

Is it safe to simply copy messages from one server and place them into the 'new' folder of an email account on another server without shutting down any of the mail servers? Both servers are Dovecot IMAP.

Answer 1

I've had experience doing live IMAP to IMAP transfer with with Google apps, I only had difficulties with very large (1000 email+) folders.

There was some loss during the transfer and you do need a computer with as much RAM as you can lay your hands on, but it was insignificant in the end.