Date: Tue, 20 Mar 2001 11:38:18 -0600 From: "Michael C . Wu" <keichii@iteration.net> To: Alfred Perlstein <bright@wintelcom.net> Cc: "Michael C . Wu" <keichii@iteration.net>, dillon@FreeBSD.ORG, grog@FreeBSD.ORG, fs@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: tuning a VERY heavily (30.0) loaded server Message-ID: <20010320113818.B52586@peorth.iteration.net> In-Reply-To: <20010320092717.R29888@fw.wintelcom.net>; from bright@wintelcom.net on Tue, Mar 20, 2001 at 09:27:17AM -0800 References: <20010320111144.A51924@peorth.iteration.net> <20010320092717.R29888@fw.wintelcom.net>
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On Tue, Mar 20, 2001 at 09:27:17AM -0800, Alfred Perlstein scribbled: | * Michael C . Wu <keichii@iteration.net> [010320 09:11] wrote: | > [Lengthy email, bear with me please, it is quite interesting. | > This box averages 30.0 load with no problems.] | | cool.. | FreeBSD zoo.ee.ntu.edu.tw 4.2-STABLE FreeBSD 4.2-STABLE #0: Tue Mar 20 11:10:46 CST 2001 root@:/usr/src/sys/compile/SimFarm i386 | > system stats at | > http://zoo.ee.ntu.edu.tw/~keichii/ | | Where's the crashdump/traceback? I'll try to get one tomorrow night, It always crashes. :) It's quite hard trying to get a crashdump when you are 15000miles away from the console. | > Physical memory is 2.5 GB. We do MFS and it croaks/crashes | > at midnight, our peak load time. We do md0, it croaks before | > peak time. | | Explain the crash. What is md0/MFS being used for? Why do you | need it? md0/MFS is used for caching the articles that BBS users read. They often read the same articles over and over again, and we find that a 128MB MFS/md0 will have 70% hitrate When our MFS/md0 fills up after long usage, the box easily dies. (We crontab clean the mfs, but sometimes the load shoots up for no reason and is not able to clean the mfs in time.) If we dont do this cache, the data for the bulletin boards | > Due to the structure of BBS's, we cannot split the load across | > different servers. We also think that we probably cannot | > get more performance out of hardware upgrades that we can afford. | > (i.e. Please don't tell us to buy a Starfire 4500 :-) We are all volunteer | > werkers at El Cheapo university budgets.) | | Well, getting hardware RAID is always a nice thing and really not | too expensive. I looked into that, it seems that hardware RAID will have less performance due to hw raid cards' onboard CPU bounding it. | > We have followed Alfred's advice to do sysctl -w vfs.vmioenable=1 | > It allows us to survive the peak load a little longer than before. | | cool.. | | > And we are putting our logs of sockstat, iostat 5, vmstat 5, | > netstat 5, dmesg, uname -a on the following URL. | > | > http://zoo.ee.ntu.edu.tw/~keichii/ | > * Anything else we can do? | | Well first off, telling us which version of FreeBSD this is... | FreeBSD zoo.ee.ntu.edu.tw 4.2-STABLE FreeBSD 4.2-STABLE #0: Tue Mar 20 11:10:46 CST 2001 root@:/usr/src/sys/compile/SimFarm i386 | Second, provide a crashdump with debug symbols, and show us | the backtrace. | | Third, consider alternatives to MFS since it seems to be a key | factor in your stability problems. If you just need a pretty | fast /tmp, I would use a softupdates partition as it's probably | more effecient than MFS/MD. The harddrives will die very quickly if we don't have MFS... -- +-----------------------------------------------------------+ | keichii@iteration.net | keichii@freebsd.org | | http://iteration.net/~keichii | Yes, BSD is a conspiracy. | +-----------------------------------------------------------+ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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