From owner-freebsd-questions  Sun Mar 30 18:35:05 1997
Return-Path: <owner-questions>
Received: (from root@localhost)
          by freefall.freebsd.org (8.8.5/8.8.5) id SAA07032
          for questions-outgoing; Sun, 30 Mar 1997 18:35:05 -0800 (PST)
Received: from root.com (implode.root.com [198.145.90.17])
          by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id SAA07012
          for <freebsd-questions@FreeBSD.org>; Sun, 30 Mar 1997 18:34:59 -0800 (PST)
Received: from localhost (localhost [127.0.0.1]) by root.com (8.8.5/8.6.5) with SMTP id SAA06129; Sun, 30 Mar 1997 18:36:31 -0800 (PST)
Message-Id: <199703310236.SAA06129@root.com>
X-Authentication-Warning: implode.root.com: localhost [127.0.0.1] didn't use HELO protocol
To: marcus@videosecrets.com (D. Marcus Arm)
cc: freebsd-questions@FreeBSD.org
Subject: Re: A question 
In-reply-to: Your message of "Sun, 30 Mar 1997 20:52:55 EST."
             <3.0.32.19970330205254.00df7c24@mail.videosecrets.com> 
From: David Greenman <dg@root.com>
Reply-To: dg@root.com
Date: Sun, 30 Mar 1997 18:36:31 -0800
Sender: owner-questions@FreeBSD.org
X-Loop: FreeBSD.org
Precedence: bulk

>Hello fellow Free-BSD lovers!
>
>My machine just locked up and displayed the following message:
>
>Mar 30 19:10:25 clip /kernel: Out of mbuf clusters - increase maxusers!
>
>Do I need to modify something in the kernel?  And how should I gauge how
>high it should be?  Any help would be GREATLY appreciated!
>
>Marcus

   Hello, Marcus. Yes, you need to increase either the "maxusers" number in
your kernel config file (which which also give you more processes and a few
other tables will be larger), or optionally add:

options "NMBCLUSTERS=<n>"

   ...where <n> is a number between 1000-4000 depending on how much network
activity (specifically, number of TCP connections) you have. Try 2000. You
can see how close you are by looking at "netstat -m". The "mbuf clusters in
use" is the important thing - the first number is the current amount and
the second number is the peak since the system was started. You want the
peak to always be less than about 2/3rds of NMBCLUSTERS (the extra third
is just a margin of safety - you don't want to run out :-)).

-DG

David Greenman
Core-team/Principal Architect, The FreeBSD Project