Date: Sun, 29 Oct 2000 08:31:05 -0600 From: "Jim C. Nasby" <jim@nasby.net> To: freebsd-questions@freebsd.org Subject: Re: RAID on the cheap Message-ID: <39FC34A9.6F37372D@nasby.net> References: <200010290700.BAA51057@cs28120-135.houston.rr.com>
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Zdenko Tomasic wrote: > > I would normally prefer scsi setup which would be better, but cost is > the issue here. What would be recommended as an adequate CPU? PIII-733? My brother just asked me the same basic question, so I ran a test: tar -cf /dev/null /usr & While this was running, I kept an eye on top and couldn't discern any increase in the cpu useage reported by the vinum process: root 18 0.0 0.0 592 8 ?? DLs Wed09PM 0:00.01 vinum: vinum daemon (vinum) tar was showing ~10% of a CPU. This box is a dual PII-375 with 4 9G 10kRPM U2W drives in a raid-5 configuration with softupdates enabled. Watching the vmstat page of systat, the disks were doing ~100 TPS and about 600kB/s. This obviously seemed a bit low. Running tar -cf ~/usr.tar /usr shows tar using about 10% of a cpu (system and interrupt combined are less than 10%, according to top), tps are down to ~75, but the drives are now doing 1.5-2.5MB/s. Still not getting the full potential (the drives are seeking their brains out... /home is a different filesystem that /usr, but they're both raid-5 volumes on the same set of drives). cp ~/usr.tar /dev/null gets us cp using 25% of a CPU, 17% going to the system. The drives are cooking along at 4MB/s. So, as someone else said, CPU speed isn't real important here, it's bus speed. -- Jim C. Nasby (aka Decibel!) /^\ jim@nasby.net /___\ Freelance lighting designer and database developer / | \ Member: Triangle Fraternity, Sports Car Club of America /___|___\ Give your computer some brain candy! www.distributed.net Team #1828 Get paid to surf!! http://www.enteract.com/~nasby/alladvantage.html To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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