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From: Mark Blackman <mark@exonetric.com>
In-Reply-To: <CB920690.DFDE%traiano.welcome@mtnbusiness.co.za>
Date: Fri, 23 Mar 2012 09:15:45 +0000
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To: Traiano Welcome <Traiano.Welcome@mtnbusiness.co.za>
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Cc: freebsd questions <freebsd-questions@freebsd.org>
Subject: Re: FreeBSD: syslog-ng: I/O error occurred while writing;
	fd='xx', error='No buffer space available (yy)'
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On 23 Mar 2012, at 08:58, Traiano Welcome wrote:

> Hi Mark
>=20
>=20
> On 22/03/2012 13:54, "Mark Blackman" <mark@exonetric.com> wrote:
>=20
>>=20
>> On 22 Mar 2012, at 11:40, Traiano Welcome wrote:
>>>=20
>>> Somehow this doesn't strike  me as a large volume of throughput =8A
>>=20
>> Ok, fair enough. You might try simulating the problem by deliberately
>> overloading the syslog UDP output and confirm the cause.
>=20
>=20
> Apparently this means that the network driver has "filled" up with
> packets. John Baldwin over at freebsd-net@ advises I up the number of
> descriptors assigned to igb to the maximum
> to workaround this using the hw.igb.maxtxd tunable you would set. So =
I've
> rebooted with the following in loader.conf:
>=20
> hw.igb.rxd=3D4096
> hw.igb.txd=3D4096
>=20
>=20
> This seems to be working so far. What I've noticed is that the system =
is
> using far  less RAM than previously, and CPU utilisation is up to 100% =
of
> one core, load average is 1, which I would guess means that the system =
is
> now processing a lot more syslog  data now that "more packets are =
making
> it through the network driver".
>=20
> I'll keep monitoring over a 24 hour period though, to see how =
effective
> this is.

Right, good news. Interesting that you need to tweak network drivers.

- Mark