Date: Sat, 14 Dec 2002 17:23:11 -0600 From: "Jack L. Stone" <jackstone@sage-one.net> To: Josh Brooks <user@mail.econolodgetulsa.com>, freebsd-questions@FreeBSD.ORG Subject: Re: NMBCLUSTERS over 4096 dangerous in any way ? Message-ID: <3.0.5.32.20021214172311.01244eb8@mail.sage-one.net> In-Reply-To: <20021214143213.E77087-100000@mail.econolodgetulsa.com>
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At 02:36 PM 12.14.2002 -0800, Josh Brooks wrote: > >Hi, > >I have a firewall that is starting to get a little overworked. I >currently have this line in my kernel config: > >options NMBCLUSTERS=4096 > >and I am starting to hit that limit: > >276/4096/4096 mbuf clusters in use (current/peak/max) > >So, the obvious response is to increase that NMBCLUSTERS value. > >----- > >However, in all the examples and discussion I have seen, I have never seen >anyone discuss raising it above 4096. I have no indication that raising >it to ... say ... 8192 would be dangerous/risky, but I think I should ask >just to make sure. > >The system is a P3-600 with 256 megs physical ram, and 128 megs swap. >This system has no other duties than firewalling. System is running >4.4-RELEASE. > >SO: > >1. any comments on raising NMBCLUSTERS to 8192 ? any other values that >need to be tuned to support that ? > >2. what is the max I could safely raise NMBCLUSTERS to ? > > >thanks! > > Further to my earlier post on this subject and that I chose to use 8192 in my kernel for NMBCLUSTERS, I found this note in my files from some research: ######################################################################## A parameter you may need to change for a busy server, gateway or firewall is NMBCLUSTERS. This controls the size of the kernel mbuf cluster map. On your computer, if you get messages like "mb_map full", you need to increase the value of this parameter. If traffic on a network interface stops for no apparent reason, this may also be a sign that you need to increase the value of NMBCLUSTERS. A reasonable value on the i386 port with most 100Mbps ethernet interfaces (no matter how many the machine has) is 8192. option NMBCLUSTERS=8192 ######################################################################## Best regards, Jack L. Stone, Administrator SageOne Net http://www.sage-one.net jackstone@sage-one.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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