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Date:      Mon, 07 Dec 1998 15:15:13 -0500
From:      Rob Miracle <rwm@tansoft.com>
To:        aron <aron@flyingcroc.com>
Cc:        FreeBSD-questions@FreeBSD.ORG
Subject:   Re: NMBCLUSTERS: Max Sane Values??
Message-ID:  <4.1.19981207150722.00933230@central.TanSoft.COM>
In-Reply-To: <Pine.NEB.4.04.9812061040440.2652-100000@chaos.necropolis.o rg>

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At 10:52 AM 12/6/98 -0800, you wrote:
>The handbook says max for NMBCLUSTERS is 4096 however I am pretty sure
>that it is out of date...

We are running 2.2.7 on our NFS server and we reboot almost daily with an out
of mbufs error.  We have maxusers defined as 128 and the param.c file is
defining NMBCLUSTERS as 512 + maxusers * 16 and nmbufs = NMBCLUSTERS * 4, which
results in 2560 clusters and over 10,240 nmubs.

>I currently have NMBCLUSTERS set to 10240 with no ill effects yet i still
>get panics every two days or so... (the box mostly runs tons of apache
>procs)

>and why does this situation cause a kernel panic anyway?? I seem to
>remember a similar situation with NetBSD a while back which cured the
>kernel panics when mbufs were exhausted and thought freebsd had also
>corrected the problem even earlier....
>
>any info or pointers appreciated.

netstat -m reports far fewer mbufs in use that we think we have and it shows a
large amount of kbyte usage:

346 mbufs in use:
        265 mbufs allocated to data
        73 mbufs allocated to packet headers
        6 mbufs allocated to protocol control blocks
        2 mbufs allocated to socket names and addresses
165/202 mbuf clusters in use
447 Kbytes allocated to network (83% in use)
0 requests for memory denied
0 requests for memory delayed
0 calls to protocol drain routines

We have been having period panics in 2.2.7 and earlier with an out of mbufs
error on our main NFS server which is also running the database and another
data server.

This is starting to drive me nuts and management is getting a bit upset about
the downtime and they are throwing other OS's around (hissssss).

I need some help on this.

Rob


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