Date: Thu, 18 Nov 1999 09:38:52 -0000 From: "Majid Almassari" <majid@ibroadcast.net> To: "Sheldon Hearn" <sheldonh@uunet.co.za> Cc: "questions@FreeBSD.ORG" <questions@FreeBSD.org> Subject: Re: NMBCLUSTERS Message-ID: <007301bf31a8$b9dd7b70$8e1d91d8@ibroadcast.net> References: <15786.942915596@axl.noc.iafrica.com>
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I really appreciate your suggestions Sheldon, Actually the KERNEL is currently running with these settings, i.e., NMBCLUSTERS=8192 it was compiled and used and the messages is produced with that KERNEL running. even though it does not have the quotation mark around it. We are running FreeBSD Release 3.2. Most likely I would have to recompile the KERNEL reflecting the quotation around the NMBCLUSTERS=8192? Now, is this expected usage? it most likely is, We serve Video feeds out of those servers so the usage is pretty high. I doubt if it is Denial of Service (DoS) attack, but you never know I'll take a look at it. Thanx -- Majid Almassari, MSEE, MCP. Systems Administrator iBroadcast, Inc. Phone: (206) 223-5540 Email: majid@ibroadcast.net http://www.ibroadcast.net ----- Original Message ----- From: Sheldon Hearn <sheldonh@uunet.co.za> To: Majid Almassari <majid@ibroadcast.net> Cc: <questions@FreeBSD.ORG> Sent: Thursday, November 18, 1999 8:59 AM Subject: Re: NMBCLUSTERS > > > 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 > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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