[Dovecot] Connection queue full on 2.0.8

Timo Sirainen tss at iki.fi
Wed Dec 15 18:29:36 EET 2010

On Wed, 2010-12-15 at 17:07 +0100, Thomas Hummel wrote:
> On Wed, Dec 08, 2010 at 08:42:42PM +0000, Timo Sirainen wrote:
> > You reached the default limits of imap-login processes. You probably want to
> > switch to high performance mode for them: http://wiki2.dovecot.org/LoginProcess
> By the way, 
> what does count for one "client" in the "client_limit" setting ? For instance,
> if a client (User Agent like Thunderbird) is configured to open 5 connections,
> does that increase the client count by 5 for this limit ? 

Depends.. One client is one unix/tcp connection for that specific
service process. Then it depends on the service's settings:

If service imap-login has been configured with service_count=0, it also
triggers client_limit=$default_client_limit. Then you can have that many
simultaneous connections to that process. But imap-login processes stop
handling connections after user has logged in, except if the connection
was using SSL/TLS.

imap processes then typically have client_limit=1 and instead the
process count increases.

So with Thunderbird that creates 5 SSL connections you'll get:

 - 5 less clients available for imap-login service
 - 5 less processes available for imap service

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