[Dovecot] Migrating existing local Maildir structure to dovecot server Maildir

[Andreas Ntaflos]

On Monday 16 November 2009 12:35:35 Halim Issa wrote:
> On 16/11/2009, Andreas Ntaflos <daff at dword.org> wrote:
> > On Friday 13 November 2009 15:00:09 Halim Issa wrote:
> >> Hello,
> >>
> >> I'm about to migrate a number of existing users who have been
> >> using POP3 with emails stored locally in KMail's Maildir format
> >> into an IMAP solution based on Dovecot.
> >>
> >> Will it be possible to simply move all the KDE Maildir folders
> >> from the local PCs to the Maildir folder on the IMAP server
> >> running Dovecot and then have the emails accessible on the server,
> >> or will this most likely mess up the Dovecot index files?
> >>
> >> If this causes index file trouble, is there any way to force a
> >> re-indexing of all these files, or is there another recommended
> >> way of migrating up to 7 years of email communication from local
> >> hosts to the IMAP server, for later putting them in folders?
> >
> > I don't think the migration of the Maildir structure itself is the
> > problem. Dovecot has no problem reading it, no matter where it came
> > from, as long as it is a proper Maildir structure. Existing indexes
> > should not be affected.
> >
> > The indexes that KMail writes, however, will probably not migrate
> > well or at all. I do not know anything about the index format KMail
> > uses but converting it to something Dovecot understands and accepts
> > seems troublesome and difficult to me.
> >
> > This means that you can copy all existing, local Maildirs over to
> > the server (you can even put them in subfolders in existing
> > accounts) and Dovecot will read them just fine. But it also means
> > that Dovecot will very probably present them to the user as new
> > messages, never seen before.
> >
> > But do yourself a favour and test any procedure you plan on
> > implementing properly and extensively before actually implementing
> > it. Otherwise it could end up messy and irreparable.
>
> Thanks much for your thorough answer! I'll make sure to test
> extensively.
>
> One thing came to mind - would it be possible to use Dovecot and
> Disconnected IMAP itself for the transfer, and perhaps thus keep the
> indexes?
> If I move the messages from the local mailbox to the IMAP mailbox
> from within Kmail it should perhaps keep the status?

Interesting idea, but I don't know how well or even if KMail handles 
moving messages from one account to another. In any case it seems worth 
a try.

> Also - is there any documentation anywhere (or tips on better google
> search terms) on what is stored in these indexes? I suppose apart
> from Read/New status, it also contains whether or not there have been
> replies to the mail and on what date the email was replied to?

If you are talking about the indexes KMail keeps I suppose you should 
try one of the KDE-PIM-related mailing lists. For Dovecot's index files 
you should ask Timo or browse the wiki, maybe there is some 
documentation about it somewhere. I myself don't know anything about 
the format of any of the index files, sorry.

Andreas
-- 
Andreas Ntaflos
Vienna, Austria

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