[Dovecot] Converting mbox to Maildir, all prior read messages are downloaded as new

[FiL]

Timo Sirainen wrote:
> On 24.5.2007, at 22.22, Eric and Barbara Sammons wrote:
>
>> I am running dovecot 0.99.  Everything works great; however, now I am 
>> looking at several different tools to convert mbox to Maildir.  It 
>> seems the tools, mb2md.pl, perfect_maildir.pl, and others all do what 
>> they claim; however, when the messages are converted and they are 
>> stored in Maildir/cur, the email clients download these messages as new.
>
> I guess you're talking about POP3. You'd need to be able to preserve 
> the POP3 UIDLs (see http://wiki.dovecot.org/Migration), which would 
> require that you also preserve the IMAP UIDs in the mbox -> Maildir 
> switch. Unfortunately I'm not aware of any scripts that preserves the 
> UIDs, although it wouldn't be difficult to write support for that.
>
This is not only about POP3, as far as I can tell. If you converting
mbox to Maildir (dovecot to dovecot) - UIDs change. And if you have your
client set to cache all the messages and
you have over 1Gb in your mail... well, it will be transferring all your
mail again. Deleting the old one (as it is not on the server anymore)
and re-downloading new ones.
It would be nice to have Convert plugin, that preserves UIDs and
UIDVALIDITY values.

P.S. A little unrelated question about convert plugin.

I have all my mbox-es in /raid/mbox/%u
I have set convert_mail = mbox:/raid/mbox/%u:INBOX=/var/mail/%u in the
dovecot.conf.
But for some reason the folder with mail doesn't get renamed after
conversion. Is that the way it should be?

Of course, it tries to convert the same boxes next time I log in.

FiL