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Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!msuinfo!agate!spool.mu.edu!sol.ctr.columbia.edu!news.kei.com!news.mathworks.com!news2.near.net!das-news2.harvard.edu!cantaloupe.srv.cs.cmu.edu!bb3.andrew.cmu.edu!andrew.cmu.edu!aw2t+ From: "Alex R.N. Wetmore" <aw2t+@andrew.cmu.edu> Newsgroups: comp.os.386bsd.questions Subject: dismal file system performance and odd scsi stuff Date: Sat, 29 Oct 1994 13:23:56 -0400 Organization: Senior, Math/Computer Science, Carnegie Mellon, Pittsburgh, PA Lines: 30 Message-ID: <oigcIge00iUzI28UlV@andrew.cmu.edu> NNTP-Posting-Host: po2.andrew.cmu.edu I'm trying to figure out how to get the best file system performance out of my system (486sx/25, 250 meg WD IDE, 1gig Micropolis 4110 SCSI w/ AHA1542C). I know about tunefs, and have even played with it a bit, but can't get iozone speeds about 400k per second or so (on the SCSI, even worse on the IDE). SCSI performance is what I'm looking for, since there isn't much on the IDE. Is there any way that I can figure out the ideal performance options for a drive? Should I just play around. I read the chapter on the filesystem in the System Manager Manual (SMM chapter 14), but it didn't go into this much. I also poked around on minnie, but couldn't find anyone answering this question before (asked a few times, no answers). This also might be more of a hardware based question. I've noticed that I get exactly one megabyte per second using dd to read data from my sd0a device. (I used the command "dd if=/dev/sd0a of=/dev/null bs=4k count=1024). This seems like a very odd number to get constantly, as if its being throttled that low for some reason. Is there anything in my CMOS bus setup or scsi controller setup that could cause such odd transfer rates? If someone can tell me how to do a similar thing under DOS (I don't have a dos filesystem on this drive) or Windows NT (there is an NTFS partition on the drive) I'd be interested in seeing what I get there. I did notice that doing the same dd command but on wd0a instead of sd0a I only get around 500k/sec, even though Norton SI (6.0 I think) shows about 900k transfer rates on the drive. I expect to be able to get >1 MB for the IDE and >2 MB for the SCSI (its a 5400 rpm drive). thanks, alex (alex@phred.org)