I'm running a test migration right now which is making me cringe. My 40 users are currently using Mail.app on 10.4.x w/ POP3 to access their corporate email (sendmail, dovecot). I'm testing a migration using a mailbox from a user who never sorts anything. Inbox is 7000 messages and sent mail is about 7000 as well.
I added the new zimbra server (open source 5.0.2 on Ubuntu 6.06 LTS) as a 2nd account using IMAP. First I rebuilt the sent mail folder. Once complete, I quit then re-opened Mail.app. I then tried to copy (not move) all 7k messages to the Sent folder on the Zimbra server. It failed about 10mins into it saying '6000 messages could not be copied'. I then tried to do it batches of 100-500. That seemed to work up to a point, but then no matter how many I did, it would complain about some of them. The problem is, I don't know which ones so by re-copying, I was duplicating emails.
I've been wanting to move away from POP3 for years, just never had the opportunity really. I'm thrilled w/ Zimbra and looking forward to using it, but the migration process scares me.
Has anyone else out there had success migrating POP3 users running Mail.app with 1000's of messages stored on their local computer?
Looks like Mail.app stores the Inbox and Sent in mbox format, so next step is to try to use the migration script too (name evades me). Thanks in advance for any insight. To my users, the success of the new mail server (Zimbra) really hinges on a successful migration.