Date: Thu, 12 Aug 1999 09:07:35 -0700 From: Doug <Doug@gorean.org> To: Dag-Erling Smorgrav <des@flood.ping.uio.no> Cc: ndear@areti.net, freebsd-isp@FreeBSD.ORG Subject: Re: mbuf clusters. Message-ID: <37B2F147.1BFC9C39@gorean.org> References: <199908111513.QAA21355@post.mail.areti.net> <37B1B1EE.4DCF214F@gorean.org> <xzphfm5th32.fsf@flood.ping.uio.no>
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Dag-Erling Smorgrav wrote: > > Doug <Doug@gorean.org> writes: > > It's impossible to answer this question intelligently without knowing your > > version of the OS and your current kernel maxusers setting, not to mention > > memory, processor, etc. However in general for a short term crisis > > situation like this you can go to 512 maxusers and 15000 NMBCLUSTERS on a > > 2.2.8 system, assuming that you have enough ram. > > No. Increasing MAXUSERS beyond 128 on a pre-3.2 system is very risky. > The problem is not RAM, but kernel virtual memory space. I ran highly loaded IRC servers like that for years. In 2.2.8 increasing maxusers beyond 512 or NMBCLUSTERS above 15k is a pessimization, but those levels are safe as long as you have the physical ram to handle it. > BTW, there's no point in increasing MAXUSERS if you set NMBCLUSTERS > separately. Unless you also need more of those other things too. :) In our case it was maxfiles that was the issue. One of my servers often ran 5,000 simultaneous connections and we needed about 2.5 times that in open files to handle it all. We could have gotten by with just adjusting those two parameters by hand, but things seemed to run "better" with maxusers set higher, and we could afford the wasted space in the process table. I suggested raising everything at once because this is/was a crisis situation for the user. However I also suggested that once he reaches a stable level he should tune it back down to his actual needs. Doug To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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