Index: [Article Count Order] [Thread]

Date:  Tue, 11 Mar 2008 19:20:03 -0400
From:  "Darrell D. Mobley" <dmobley (at mark) uhostme.com>
Subject:  [coba-e:12248] Re: [testing] dovecot udpate
To:  <coba-e (at mark) bluequartz.org>
Message-Id:  <020c01c883ce$6fe3a270$6400a8c0@HPPAVILION>
In-Reply-To:  <47D70514.7000402 (at mark) dogsbody.org>
References:  <327DE0A0-4C10-47A0-B6F7-71D79103911B (at mark) alpha.or.jp> <BAY129-DAV76CAC02DDE71D0BCF8FBECA0E0 (at mark) phx.gbl> <D0D0ED72-1F66-473E-A0EE-1D43EC435A28 (at mark) alpha.or.jp> <BAY129-DAV123818537FFE857E7E51E9CA0F0 (at mark) phx.gbl> <47D70514.7000402 (at mark) dogsbody.org>
X-Mail-Count: 12248

If you look in config file snippet, you will notice the '#' in front of the
line with 128 in it, meaning it was commented out on production machines.
He was recommending activating it and setting it to 12.

> -----Original Message-----
> From: Dogsbody [mailto:dan (at mark) dogsbody.org]
> Sent: Tuesday, March 11, 2008 6:18 PM
> To: coba-e (at mark) bluequartz.org
> Subject: [coba-e:12247] Re: [testing] dovecot udpate
> 
> 
> >>> I have the following issues with this.
> >>> #1 This will not fix to the db crashing problem
> >>
> >> I'm not sure this package fixes or not,
> >> If you are right, what is the cause of db crashing issue?
> >> And, will you send us your patch to fix it?
> >
> > The problem is in the way dovecot starts new child processes.  they
> > double their amount until the limit set by this setting is reached..
> > which by default is unlimited.  When a dos attack and or a exchange
> > server opens multiple auth sessions the db program can't keep up.  The
> > solution is to limit the potential processess...  (The version update is
> > just good pratice)
> >
> > @@ -159,7 +159,7 @@
> > # we check only once in a second if new processes should be created - if
> > all
> > # of them are used at the time, we double their amount until the limit
> > set by
> > # this setting is reached.
> > -#login_max_processes_count = 128
> > +login_max_processes_count = 12
> 
> Just trying to understand, not criticizing anyone.
> 
> As I understand it the problem is not so much with dovecot but with the
> auth
> plugin?  So it's the auth plugin we should really be fixing?
> 
> You say the default is unlimited but above your changing it from 128 to
> 12?
> 
> Surely it's better to keep dovecot at 128 and change auth to return a fail
> if
> things start to get busy?
> 
> Just trying to understand.
> 
> Dan