The end of Dovecot Director?

[Tom Sommer]

To be clear, you are removing the Director...

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Tom

On 2022-10-21 13:28, Aki Tuomi wrote:
> To be clear, we are not removing proxying features from Dovecot either. 
> Just the director ring feature.
> 
> 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.
>> >