[Dovecot] Best way to migrate from Qpopper to Dovecot

[Torsten]

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:

1.
- 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)

2.
- 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