[Dovecot] troubles with 1.1.8 and squirrelmail over HTTPS
f.bonnet at esiee.fr
Mon Jan 26 17:45:24 EET 2009
Setting up imapproxy on a third machine greatly improve
performances on my mailhub which doesn't refuse connexions
Thanks a lot for your help !
Jack Stewart wrote:
> Frank Bonnet wrote:
>> Timo Sirainen wrote:
>>> On Thu, 2009-01-15 at 16:25 +0100, Frank Bonnet wrote:
>>>> I had to increase the max_mail_processes to 8192
>>>> to have a functionnal IMAP server with normal clients AND
>>>> squirrelmail clients
>>>> 8192 sounds enormous to me , any infos welcome !
>>> How many imap processes have you running typically?
> I don't know if this will help or not - I'm taking my comments offline
> because it isn't clear if they are related to your core problem. Also,
> they seem to be specific to high usage servers/people.
> We're not 1.1.8 yet but I've spent a reasonable amount of time tweaking
> the Linux side.
> We run at about ~1300 processes per server.
> Squirrelmail does a login/logout on every single page that is clicked.
> So I've found that running an imap proxy (such as the one at
> imapproxy.org really helps). It creates some additional connections but
> they get re-used pretty frequently.
> If 1.1.8 isn't logging out quickly, or not cleanly shutting down the
> connection, or something similar, that could explain additional
> connections. What does netstat -an show? On some O/S's the process will
> disappear from ps but not be fully released until the socket/connection
> disappears (in this case tcp). If you have a bunch of WAIT/FIN_WAIT's
> something like this seems pretty likely.
> I've found that going through localhost allows you to bypass TLS while
> still enforcing TLS for non-localhost connections. It's pretty nice for
> overhead/connect speed. Also, an imap proxy may need a non-encrypted
> Besides the dovecot max_ ... settings, in our system you need to tweak
> limits.conf and bump up the limits via the ulimit command in the dovecot
> init script. Open file descriptors and process limits seem to be the
> main settings.
> After this, you get into kernel tuning such as inotify settings.
> Let me know if you have any questions. If some of this helps, we might
> want to feed it back into the list.
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