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Date:      Wed, 26 Nov 2003 07:23:24 +1000 (EST)
From:      Andy Farkas <andyf@speednet.com.au>
To:        Bill Vermillion <bv@wjv.com>
Cc:        freebsd-isp@freebsd.org
Subject:   Re: start multiple sendmail daemons from rc.conf?
Message-ID:  <20031126070221.R17841@hewey.af.speednet.com.au>
In-Reply-To: <20031125204822.GD6772@wjv.com>
References:  <3FC395B3.C59E4AC3@tcworks.net> <20031125175601.GA4988@wjv.com> <20031126055846.X17841@hewey.af.speednet.com.au> <20031125204822.GD6772@wjv.com>

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Bill Vermillion wrote:

> > >So even though sendmail says it is rejecting connections
> > >(twice!), it then goes and accepts two more! Grrr.
>
> Well it's sort of hard to let the far systems know they shouldn't
> be sending any.  If you look at the config file you will see that
> when sendmail reaches a certain limit it will not accept any more
> connections.  So your resources are too low [as noted in the other
> poster comment below] as you run out of resources before you hit
> the limit that is in Sendmail. [see your .cf file and you could
> set the load average where you just queue messages and the point
> where you reject messages lower]
>
> > Thrash is correct and it would appear it happening from the
> > messages above. Sendmail checks the load average each time a new
> > request is received. If the average is above the threshold it
> > puts out that message and doesn't handle the request. Obviously,
> > when PIDs 71848 and 71861 were started the load average was
> > below the threshold. Running out of swap space is never going to
> > be a good thing. You need more memory or more swap space.
>
> Unless he's modified the sendmail.cf for different load values
> and moved them too high, then he probably needs both more memory
> and more swap space.  And of course more memory means you need to
> add more swap space.
>
> Until he gets more memory he can add swap space - man 8 swapon -
> but to blame sendmail for an under powered or mis-configured system
> is wrong.

I know exactly what happened to my system. I was there watching it self
destruct. But the beauty of FreeBSD is its stability; the box is still
running and hasn't even been rebooted.

Yep, it needs more RAM and more swap. But that aint gonna happen :)

Some background on my setup: sendmail, procmail, bogofilter, and
amavis/uvscan. sendmail receives a message, sends it to amavis which
spawns a uvscan, then procmail bogofilters it. Works well, but is rather
resource intensive (and as you've noticed, this box is under-resourced).

If I disconnect from the 'Net for a few hours, mail gets queued upstream,
and when I reconnect, vast quantities of email come in all at once
spawning hundreds of processes. (the poo hits the fan at around 300 procs)

My sendmail.cf has this in it:

O QueueLA=3
O RefuseLA=4
O DelayLA=2
O MaxDaemonChildren=16
O ConnectionRateThrottle=3

but the situation can still occur :)

--

 :{ andyf@speednet.com.au

        Andy Farkas
    System Administrator
   Speednet Communications
 http://www.speednet.com.au/




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