AW: The end of Dovecot Director?

[MK]

>To be clear, we are not removing proxying features from Dovecot either. Just the director ring feature.
To be realy clear, you are not removing the proxy feature in dovecot that can be used to proxy users to different backend server on which 
the users mailboxes are stored?

Thanks Oliver 

>Aki

> On 21/10/2022 14:14 EEST Amol Kulkarni <amolk112k at gmail.com> wrote:
> 
> 
> Nginx has an mail proxy for pop, imap, smtp.
> Can it be used instead of director ?
> 
> 
> On Fri, 21 Oct 2022 at 16:21, <hi at zakaria.website> wrote:
> > On 2022-10-21 10:51, Zhang Huangbin wrote:
> >  >> On Oct 21, 2022, at 5:23 PM, hi at zakaria.website wrote:
> >  >>
> >  >> I was wondering if one can achieve the same implementation with  
> > >> haproxy without dovecot director?
> >  >
> >  > The most important part of Director is it makes sure same mail 
> > user  > always proxied to same backend IMAP server.
> >  >
> >  > If mailbox is in Maildir format (and stored on shared storage 
> > like  > NFS), accessing it from different server may corrupt Dovecot 
> > index  > files and mailbox becomes unaccessible. Director perfectly 
> > avoids this  > issue.
> >  >
> >  > HAProxy can proxy mail user from same client IP to same backend 
> > IMAP  > server, but not same mail user from different IPs.
> >  >
> >  > Quote (https://doc.dovecot.org/admin_manual/director/dovecotdirector/):
> >  >
> >  > "Director can be used by Dovecot’s IMAP/POP3/LMTP proxy to keep a  
> > > temporary user -> mail server mapping. As long as user has 
> > simultaneous  > connections, the user is always redirected to the 
> > same server. Each  > proxy server is running its own director 
> > process, and the directors are  > communicating the state to each 
> > others. Directors are mainly useful for  > setups where all of the 
> > mail storage is seen by all servers, such as  > with NFS or a cluster filesystem."
> >  >
> >  > ----
> >  > Zhang Huangbin, founder of:
> >  > - iRedMail: Open source email server solution: 
> >  > https://www.iredmail.org/
> >  > - Spider: Lightweight, on-premises Email Archiving Software: 
> >  > https://spiderd.io
> >  
> >  Aha makes sense, although I was not able to see how can index files 
> > be  corrupted when its if will going to be updated, its in same 
> > manner as  from different connection, e.g. opening email account 
> > from different app  clients, with different connections, does not corrupt the index files?
> >  
> >  Also, Is it the issue Director resolving as well its with 
> > maintaining  the logged in dovecot connection to same backend? 
> > Anyhow, thanks for  your valuable efforts in clearing this :)
> >  
> >  I wondered if there is any other solution to avoid corrupting index  
> > files? Perhaps if dovecot offer database indexing as well as login  
> > sessions, it seems that this would eliminate Director requirement, 
> > and  offer better high availability, as for now userdb/authdb is 
> > only  available per my knowledge, and using database cluster 
> > resolves the  issue with user and auth queries during simultaneous 
> > connections to a  different backends.
> >  
> >  Otherwise, it seems in large enterprise deployment with high  
> > availability a Director implementation will be needed, hopefully we 
> > will  find an alternative solution by the time Dovecot 3 is released.
> >  
> >  I might need to get my head around building dovecot with customised  
> > modules and review the code which was removed and return it back, if  
> > anyone is planning to this, and well off ahead of me, please let me  
> > know, we might be able to help one another.
> >  
> >  With thanks.
> >  
> >  Zakaria.
> >