[Dovecot] Best way to migrate from Qpopper to Dovecot

Hi List,

what do you think is the best way to migrate (to a new maschine) round about 30000 mboxes (Qpopper) with an amount of 43Gigs data, to maildir format (Dovecot). I think there are two ways:

• stop services (smtp and pop3) on the old maschine
• copy the mboxes to the new maschine
• run a conversion script (for excample: "Perfect_maildir" http://perfectmaildir.home-dn.net/)
• start the services on the new maschine (smtp and Dovecot)

• tell the users to use the new server (from the day X) with the new feature (imap)
• stop the smtp on the old maschine on day X
• leave the old maschine active for a month or so (let users get their "old" mail)

With the first alternative we have a high downtime, because of copying the mboxes and converting the stuff.

What do you think?

Thanks Torsten