Date: Wed, 24 Nov 2004 21:30:19 +0100 From: Thomas Eisenbarth <eisenbarth@domecon.de> To: freebsd-security@freebsd.org, akhthar@carmatec.com Subject: Re: Mbuf errors Message-ID: <200411242130.24229.eisenbarth@domecon.de> In-Reply-To: <200411250002.37764.akhthar@carmatec.com> References: <200411250002.37764.akhthar@carmatec.com>
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Hi there,
Am Mittwoch, 24. November 2004 19:32 schrieb Akhthar Parvez. K:
> All mbuf clusters exhausted, please see tuning(7).
Did you have a look at this ?
> 3704/6656/6656 mbuf clusters in use (current/peak/max)
> 16980 Kbytes allocated to network (85% of mb_map in use)
> 106522 requests for memory denied
> 1545 requests for memory delayed
tuning(7):
kern.ipc.nmbclusters may be adjusted to increase the number of network
mbufs the system is willing to allocate. Each cluster represents appr=
ox-
imately 2K of memory, so a value of 1024 represents 2M of kernel memory
reserved for network buffers. You can do a simple calculation to figu=
re
out how many you need. If you have a web server which maxes out at 10=
00
simultaneous connections, and each connection eats a 16K receive and 1=
6K
send buffer, you need approximately 32MB worth of network buffers to d=
eal
with it. A good rule of thumb is to multiply by 2, so 32MBx2 =3D 64MB=
/2K =3D
32768. So for this case you would want to set kern.ipc.nmbclusters to
32768. We recommend values between 1024 and 4096 for machines with mo=
d-
erates amount of memory, and between 4096 and 32768 for machines with
greater amounts of memory. Under no circumstances should you specify =
an
arbitrarily high value for this parameter, it could lead to a boot-time
crash. The -m option to netstat(1) may be used to observe network clu=
s-
ter use. Older versions of FreeBSD do not have this tunable and requi=
re
that the kernel config(8) option NMBCLUSTERS be set instead.
greetings
=2D-=20
Thomas Eisenbarth eisenbarth@domecon.de
Donau-Ries Media-Consulting http://www.domecon.de
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