Advice needed: Migration Dovecot to Kolab Cyrus.

[Mat Cantin]

On 2013-03-20 1:56, Winfried Ritsch wrote:
> Hello,
> 
>  I set up a new Kolab 3.0 on Debian wheezy and I am quite a newbie on 
> this.
> (Thanks for this work, I installed it on a fresh server setup quite 
> nicely and
> it is working quite well, with some problems, not urgent needed.) Now 
> I want
> to switch to the new server:
> 
> 
>  What tools to use for migration of maildirs from exim/dovecot to 
> Kolab 3 ?
> 
> 
> Here my try:
> 
>  - I created same users on Kolab, adjusting the uid so login should be 
> the
> same,
> 
>  I used imapsync from Fedora free source: 
> https://fedorahosted.org/imapsync/
> 
>  with options:
>   --tls1 --tls2 --syncinternaldates --delete2  --noexpunge --subscribe
> 
>   (no --delete2folders since it would erase default folders of Kolab)
> 
> Since mailboxes are quite big, I did a pre-sync during running system. 
> after
> that during switching (exim mailserver down, firewall blocked imap) I 
> did a new
> sync:
>   - some of mails where doubled, folder structure was broken.
> 
> on this new imapsync a lot of mails are copied again, which will take 
> more
> then 8 hours, to long for a mailserver downtime.
> 
> So now I switched back to old sever before completing.
> 
> Like stated before: Has anyone a hint how it could be done more 
> smoothly ?
> 
> mfg
>  Winfried Ritsch

I've quite successfully used offlineimap [http://offlineimap.org/] on 3 
sites with over a dozen users, and with a couple of mailboxes over 20GB. 
The best part was that I was able to have both the old system and new 
system accessible by the users, so they could switch back and forth if 
they wanted to. Although the initial sync does take some time, once it 
was done I had the mailboxes sync every 10 to 15 minutes so email delays 
were minimal, there was no downtime for the end user, and they were able 
to switch to the new system at their leisure.

A couple things to note: you do need the passwords for the users you're 
migrating, and the initial sync would sometimes copy a message but error 
out on message UID mismatch so it had to be re-run several times on big 
mailboxes (I just created a loop script). The default for offlineimap 
was to copy the message on error, so I didn't loose any messages, and 
the next run would start at the next message.

I can share my config file if you want, it took me a little while to 
get it right, especially figuring out how to handle converting Dovecot's 
INBOX subfolders to Cryrus' regular folder, and how to map folders with 
different names like the "Sent Items" folder to the "Sent" folder.

--
Mat