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Newsgroups: comp.os.386bsd.questions Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!msuinfo!agate!usenet.ins.cwru.edu!lerc.nasa.gov!purdue!mozo.cc.purdue.edu!staff.cc.purdue.edu!bj From: bj@staff.cc.purdue.edu (Ben Jackson) Subject: Re: How to get better SCSI performance? [FreeBSD 1.1R/AHA1542Cf] Sender: news@mozo.cc.purdue.edu (USENET News) Message-ID: <CrqHA5.Mo2@mozo.cc.purdue.edu> Date: Tue, 21 Jun 1994 06:13:17 GMT References: <CrKBr2.8oJ@mozo.cc.purdue.edu> <Z2zQYYR.dysonj@delphi.com> <RSANDERS.94Jun19200651@hrothgar.mindspring.com> <x4wyIGv.dysonj@delphi.com> Organization: Purdue University Lines: 30 In article <x4wyIGv.dysonj@delphi.com>, John Dyson <dysonj@delphi.com> wrote: >Robert Sanders <rsanders@mindspring.com> writes: > >>Um, well, if he's getting 1/2 disk throughput with his filesystem, >>he's not getting his money's worth. [...] As the one with the slow drives, I agree! >Versions of *BSD w/o clustering will probably give only 1/2 of disk >performance on writes. I *normally* get .95 or better of my drivers >performance thru the filesystem on FreeBSD on both reads and writes. That's one of the things that makes me suspicious -- I get the same speed reading and writing, which suggests that I'm not even approaching the max possible throughput. With the card doing DMA at 8M/s, and drives capable of 5M/s sustained transfers, I see no reason why I shouldn't get more than 650k/s. >Apparently there is a difference in his drives configuration. What is *your* configuration? I believe you asked earlier what adapter I was using. As the subject says, it's an AHA1542Cf. The original message had more details about the system and SCSI chain, but the important info is: 486/66 w/16M, AHA1542Cf with a SCSI1 Maxtor, SCSI2 Quantum and SCSI2 NEC CDROM drive. On transfers that aren't all in the buffer cache, I get about 650K/s. Still soliciting suggestions, --Ben Jackson