Massive alias / bulk delivery problem

[gnd]

Yes you are right, i realized that just after i sent the email, that it
was a bit in haste.

anyway, if there is anyway how to optimize dovecot for effective
delivery of 20k+ emails within a few minutes, id be glad to know.


.. and i will have to ask the same q at postfix mailinglists

gnd/

On 7/14/20 8:12 PM, John Stoffel wrote:
> 
> gnd> we are experimenting with using Dovecot as part of a simplified
> gnd> mail stack with SQL for a internal messaging / notification
> gnd> system for our customers. Sometimes we need to send a message to
> gnd> thousands of customers at once and we do it by having aliases
> gnd> resolve to 10k and 20k+ mail accounts.
> 
> gnd> When we send such a message the server load (obviously) is very
> gnd> high for a few minutes (in case of an alias containing 10k
> gnd> addresses its around 6-7 minutes for a 2 core machine with load
> gnd> around 20-30).
> 
> gnd> Are there any optimizations or ways how to design the system
> gnd> around this problem ? Eg. is there a way how to deliver messages
> gnd> more slowly, and spread the load over longer time ?
> 
> This is not a dovecot issue, but a postfix issue.  You need to setup
> some queues in postfix to handle mail floods like this.  You should
> take this to the postfix mailing list on postfix.org, and first look
> in the archives, there have been recent discussions about this type of
> issue. 
> 
> gnd> The stack is very simple with Postfix receiving the messages and
> gnd> Dovecot acting as a LMTP and IMAP server. Mailboxes are in the
> gnd> Maildir format on disk. Customers get the messages on login, a
> gnd> PHP script connects to the mail account associated with their ID
> gnd> via IMAP and sends unseen messages in the form of a JSON.
> 
> Postfix is also sending the emails too.  :-)
> 
> John
>