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Date:      Sun, 30 Mar 1997 18:36:31 -0800
From:      David Greenman <dg@root.com>
To:        marcus@videosecrets.com (D. Marcus Arm)
Cc:        freebsd-questions@FreeBSD.org
Subject:   Re: A question 
Message-ID:  <199703310236.SAA06129@root.com>
In-Reply-To: Your message of "Sun, 30 Mar 1997 20:52:55 EST." <3.0.32.19970330205254.00df7c24@mail.videosecrets.com> 

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>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



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