dovecot/config processes open, and consuming all memory

[Aki Tuomi]

> On 17/08/2022 00:57 EEST Joseph Tam <jtam.home at gmail.com> wrote:
> 
>  
> From: Aki Tuomi <aki.tuomi at open-xchange.com>
> 
> > The *default* configuration for service config is usually just fine.
> 
> > Is there some reason you decided to modify it in first place?
> 
> 
> Are you asking me, or the OP?
> 
> 
> I guess the blunt answer is ignorance on my part.  However, I pointed
> 
> out that the docs about this setting is somewhat misleading -- it's used
> 
> to limit any potential memory leaks for long-lived processes by ensuring
> 
> it terminates periodically.
> 
> 
> I read this and thought to myself "this is a good thing to do", without
> 
> realizing that it would have the opposite effect as lingering clients
> 
> could delay service termination indefinitely.  The side effect is many
> 
> new processes are spawned to handle new clients, and eventually
> 
> the maximum process limit is reached, and chaos ensues.
> 
> 
> So for services like imap-login and others that can have lingering
> 
> clients, the only sensible values for service_limit is {0,1}.  If you
> 
> set service_limit>1, the asymptotic behaviour is like service_limit=1,
> 
> and process_limit would have to be adjusted accordingly.
> 
> 
> The docs can explain this rather wordy and subtle explanation of
> 
> service_limit, or service_limit can be constrained to values {0,1} so that
> 
> others don't blunder along the same path I did.
> 
> 
> Joseph Tam <jtam.home at gmail.com>

Thanks for the feedback, and sharing this. 

Aki