Dsync deleting mailboxes due to duplicate UIDs

[Andreas Thienemann]

Hi Sami,

On Mon, 10 Sep 2018, Sami Ketola wrote:

> I have found dsync_hashed_headers setting as a good workaround for 
> migrating mails from broken imap servers. As per RFC Message-ID should 
> be unique and we have safely used setting 
> dsync_hashed_headers=Message-ID to migrate the problematic users away 
> from the broken servers.

Just for the record, limiting the dsync_hashed_headers to _just_ the 
Message-ID is not a good solution.
Turns out, I also get the situation where Cyrus will happily sent multiple 
Message-IDs:

* 797 FETCH (UID 797 BODY[HEADER.FIELDS (Message-ID)] {127}
Message-Id: <200404140548.i3E5mYb11123 at c2.hrz.uni-giessen.de>
Message-Id: <CFA82361-8CB4-11D8-A4CA-000393101422 at MeinBu.ch>

)
1 OK Completed (0.000 sec)

My workaround now is to just ensure that I run an uneven number of doveadm 
backup runs, triggering a full sync of problematic folders.
The uneven runs delete the folders, the even ones transfer...

Anyway, thanks for the suggestion, it was a good attempt. ;-)

cheers,
   Andreas