Date: Thu, 18 Nov 1999 10:59:56 +0200 From: Sheldon Hearn <sheldonh@uunet.co.za> To: "Majid Almassari" <majid@ibroadcast.net> Cc: "questions@FreeBSD.ORG" <questions@FreeBSD.ORG> Subject: Re: NMBCLUSTERS Message-ID: <15786.942915596@axl.noc.iafrica.com> In-Reply-To: Your message of "Wed, 17 Nov 1999 10:14:56 GMT." <019601bf30e4$991bdcc0$8e1d91d8@ibroadcast.net>
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On Wed, 17 Nov 1999 10:14:56 GMT, "Majid Almassari" wrote: > according to FAQ (http://www.freebsd.org/FAQ/troubleshoot.html#AEN1135) = > you can set the NMBCLUSTERS option in the KERNEL configuration to > options "NMBCLUSTERS=3D<n>" where <n> is in the range 512-4096, my two = > questions are: > 1. We have servers that this value is set as options > NMBCLUSTERS=3D8192 is this normal to be that high even in FAQ the MAX > is 4096. I see Dag-Erling Smorgrav (one of the FreeBSD developers who manages a hard-hit IRC network) mentioning that he used 8192 in a message on the freebsd-hackers mailing list some time back. He probably knows what he's doing, so I doubt that this high value is a problem. > 2. The entry does not have a quotation mark around it as the FAQ does > is it mandatory to have those quotation marks? Now that _definitely_ depends on what version of FreeBSD you're using. If you're using 2.x.x or 3.x, you _must_ use the quotation marks. > when I issue netstat -m the settings are realized sine it reports > > 3187/3616 mbufs in use: > 2890 mbufs allocated to data > 297 mbufs allocated to packet headers > 2546/2930/8192 mbuf clusters in use (current/peak/max) Watch that peek value over time. You may be able to drop NMBCLUSTERS back down to 4096 if you can ascertain that peak doesn't go up dramatically. > The reason I'm investigating this is because I get a KERNEL panic and > the server reboots. The message in the /var/log/messages states: > /kernel: Out of mbuf clusters - adjust NMBCLUSTERS or increase maxusers! I sincerely hope you got that message _before_ you booted the kernel that has 8192 NMBCLUSTERS and not _after_! If even 8192 isn't enough, you should really try to figure out whether this high consumption is caused by expected usage, or whether you're under DoS attack. If the latter, see what you can do about protecting this machine off from such attacks. Ciao, Sheldon. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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