suse.de dovecot issues

[Aki Tuomi]

> On 10/09/2021 12:19 Bernhard M. Wiedemann <bwiedemann at suse.de> wrote:
> 
>  
> Hi,
> 
> I am one of the people taking over our new suse.de email setup
> (consisting of dovecot+rspamd+postfix)
> and wanted to report some issues we experience:
> 
> 
> 1.
> we use dovecot-director to distribute users between 2 backend servers
> that share an NFS mount.
> We found that it proxies lmtp to a different backend than imap of the
> same user and that caused NFS stale-filehandle errors on the
> dovecot-uidlist.
> It then proceeds to re-generate the dovecot-uidlist with new UIDs that
> creates trouble for users.
> 
> a) shouldn't dovecot use locks (fcntl or flock) to protect such files
> from concurrent updates?
> 
> b) could it generate uidlist in a way that re-generating it, assigns the
> same UIDs again? E.g. via hash over file content
> 
> c) how to get dovecot-director to send all traffic for a user to one
> backend?
> 
> 
> 2.
> We have 2 backends so that we can do maintenance on one of them while
> users can still access their emails through the other backend.
> However, we found that stopping dovecot on one backend left users unable
> to access their mails.
> Maybe this is related to how user auth works?
> How to get this HA setup right, so that we don't have a single point of
> failure?
> 
> 
> grep PRETTY /etc/os-release
> PRETTY_NAME="SUSE Linux Enterprise Server 15 SP3"
> 
> rpm -q dovecot23
> dovecot23-2.3.15
> 
> https://www.zq1.de/~bernhard/temp/dovecot/ has some sysreports.
> 
> Ciao
> Bernhard M.

It seems you are normalizing SQL usernames by doing SELECT username, but you are not doing it for LDAP.

See if the problem goes away with

pass_attrs = uid=username

Aki