From owner-freebsd-hackers  Thu Jan 18 04:55:05 1996
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To: davide@galactica.it
cc: hackers@FreeBSD.org
Subject: Re: panic !! 
In-reply-to: Your message of "18 Jan 1996 12:00:32 GMT."
             <199601181100.DAA25186@freefall.freebsd.org> 
From: David Greenman <davidg@Root.COM>
Reply-To: davidg@Root.COM
Date: Thu, 18 Jan 1996 04:54:54 -0800
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>Sometimes my FreeBSD 2.0 reboots saying: 
>Panic: kmem_map (or mb_map) too small !
>
>I know that this problem is caused by a vm problem,
>My system has 48mb Ram ... I think that's' enought...
>Can anyone help me to avoi this problem ?
>Can I increase the size of these maps ?

   The panic indicates that the system ran out of virtual memory for network
buffers (specifically, mbuf clusters). You can increase the amount of VM
avaliable for mbuf clusters by adding:

options "NMBCLUSTERS=<n>"

...to your kernel config file, where <n> is a number in the range 512-4096,
depending on the number of concurrent TCP connections you need to support. I'd
recommend trying 2048 - this should get rid of the panic completely. You can
monitor the number of mbuf clusters allocated/in use on the system with
netstat -m.

-DG

David Greenman
Core Team/Principal Architect, The FreeBSD Project