[Dovecot] UW-IMAP to Dovecot conversion - How to migrate the folders?

[Mike Brudenell]

Hi Patrick,

On 20 Aug 2007, at 23:21, Patrick - South Valley Internet wrote:

> I've read so much information on this that I'm a little confused as  
> to what to follow.  Here's what's going on:
>
> We just migrated away from our AIX machines which were running  
> Postfix and UW-IMAP.  We're now running Postfix with Dovecot.  I  
> already converted everyone's mbox file to maildir, but now I'm  
> having a little troubles with how to exactly populate their IMAP  
> folders.  People are saying they cannot see their folders.  These  
> 'folders' they are talking about can be found in their /home  
> directory.

I'm not sure this is relevant but...

Here we found that the standard installation of Outlook will by  
default only show folders that you have subscribed to.  This means if  
you simply convert the folders from Mbox to Maildir and put them into  
place Outlook users won't be shown them unless either:

   a) You also carefully convert the subscriptions data too (which  
the UW
      server keeps in a file called .mailboxlist), or

   b) You have everyone change their Outlook setting to show ALL  
folders instead
      only the subscribed ones.

Aside: the latter may be problematic in the longer run: I encountered  
Windows Mail (the Outlook Express replacement under Vista) for the  
first time yesterday, and this doesn't seem to have a "Show all  
folders" setting ... at least not one that I could find.  :-(

We decided it was too risky to convert people's mailboxes and  
subscriptions files: we were using UW's MBX format, which meant the  
conversion process would have been MBX --> Mbox --> Maildir :-(

Instead we're using the very-wonderful "imapsync" utility.  This is a  
Perl script that does everything using IMAP.  In particular it  
obtains the folder listing over IMAP, reads the messages over IMAP,  
writes folders/messages over IMAP and (most importantly) with the  
appropriate command line option can also copy over your subscriptions  
list.

Because all of this is done over IMAP you then don't have to worry  
about finding your old server's subscriptions file and mailbox  
structure/formats and converting them: it "just works" and everything  
ends up correctly in Dovecot's folders.

The only downsides are that imapsync is CPU-intensive, and can take  
some (wall-clock) time.  But we thought it was worth doing that way  
for safety.  :-)

Cheers,
Mike B-)

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