Re: Migration murder from 3.2 to 3.10 (Debian 11 to 13) – frontend to backend auth error

Frank Richter <[email protected]> Tue, 3 Mar 2026 16:40:40 +0100
Newsgroups gmane.mail.imap.cyrus
Message-ID <[email protected]>
Wolfgang Breyha wrote:
> On 03/03/2026 14:12, Frank Richter wrote:
>> Oh dear, thanks for pointing out this one. No, we don’t
>> use  improved_mboxlist_sort: 1 yet
> Keep in mind that you need to stop cyrus on all backends, export the
> mailboxes.db, change the setting and reimport the dump to a fresh
> mailboxes.db. After doing so you should do a "ctl_mboxlist -m" to a
> clean/empty mailboxes.db on your mupdate master after you changed the
> setting there as well. Last but not least change the setting on the
> frontends and fetch a new copy from mupdate there as well. Take note of
> #5593 on github and keep lmtp silent in the time of first sync.

Thanks. I read 
https://www.cyrusimap.org/3.4/imap/developer/thoughts/improved_mboxlist_sort.html
and made my plan similar to yours. And yes, I’ll stop the MTA, too.

> So you need a downtime. Depending on the size of your backends, primarily
> the mailboxes.db entry count, the "ctl_mboxlist -m" can take quite some time.
Downtime is scheduled.

I tested it on a test server: reimport needs ~ 3 minutes on every backend (~ 
167.000 mailboxes/folders). To push it on the mupdate master will need some 
more time (can't test in the moment).

>> … Another question: We use DIGEST-MD5 to
>> authenticate to the mupdate master, too.
>> What shall I use instead? PLAIN requires TLS, right?
>> But mupdate doesn't support TLS according to https://github.com/cyrusimap/
>> cyrus-imapd/issues/2774
>> What do you use instead?
> Anything newer and (more) secure cyrus-sasl supports. eg. SCRAM-SHA-256.

Thanks, I finally detected 
https://www.cyrusimap.org/sasl/sasl/authentication_mechanisms.html

> I also recommend scanning the currently open issues on github. There are
> some which will hurt big time if applicable and unaddressed. eg: #5548
>
> We did the 2.5 => 3.8 migration in place BTW. We did a lot of "pre flight
> tests" and there were some lessons to learn, but aside from
> improved_mailboxlist_sort nothing we couldn't handle after the upgrade
> since we build our own RPMs with local patches for open issues.
>
> By using plain debian builds YMMV in a murder env;-)
Let’s see. With Debian 11 we ended up to build our own packages with some 
patches as well.

Frank

-- 
Frank Richter, Chemnitz University of Technology, Germany


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