Cannot migrate from courier using doveadm sync

I have two systems. Up to date installation of UCS mail server with dovecot 2.2.13 and server courier imap which has all the user emails.

Trying to migrate emails from courier to dovecot, these are two articles I was reading:

I tried this in my homelab environment (but not univention) and worked great. However I cannot make it work in univention. I get error:

sudo doveadm -Dv -o mail_fsync=never -o -o -o imapc_password=password -o imapc_features=rfc822.size -o imapc_list_prefix=INBOX sync imapc:
I even tried not to use INBOX namespace.
But I get error

dsync(root): Panic: file quota-maildir.c: line 827: unreached

I tried investigating but could not find any help, the only thread on dovecot mailing list was left without answer. Last resort to get help from dovecot IRC channel but folks pointed to old version. (2.2.13 was released in 2014, 2.2.27 was released 7 months ago)

dsync migration would have been much easier and transparent, users would be able to keep using emails and once sync is done, just switch to new account. However it is not working and I would need to go and use perl migration script it seems.

I tried to disable quota plugin on dovecot, then imap sync started, but stalled. And client mails stopped working with dovecot. So no actual migration happened.


Trying to fix these interoperability problems of outdated software can become an endless story, given the experience that everybody out there would first advise to update to the latest version…

Your last resort to scripting seems reasonable. But before knitting something yourself, some tools out there already can do the job nicely. As for IMAP - to - IMAP synchronization, I’d propose IMAPSYNC ( I’m using it daily for archiving purposes, and it never lost even one message. You would have to install it on only one of the machines; let’s see which one is easier to prepare.

If it turns out to be too complicated: the author of the tool has put up a page of similar tools he has found, at . Perhaps one of those better suits your needs.

Frank Greif.

Thank you for reply. I suppose I can setup a separate server for imapsync, it does not have to be on my mail server? As I would wish to keep it as clean as possible.


Yes, this is possibale and a good idea.