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Date:      Tue, 6 Jan 2004 11:56:46 -0600
From:      Dan Nelson <dnelson@allantgroup.com>
To:        Mike Maltese <mike@pcmedx.com>
Cc:        questions@freebsd.org
Subject:   Re: Poor SCSI disk preformance
Message-ID:  <20040106175645.GE38169@dan.emsphone.com>
In-Reply-To: <012d01c3d47d$40fe8b50$f4f0a8c0@pcmedx.com>
References:  <000201c3d461$eea71770$0301a8c0@office.cpainc.net> <012d01c3d47d$40fe8b50$f4f0a8c0@pcmedx.com>

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In the last episode (Jan 06), Mike Maltese said:
> > I also had (meaning it is not currently attached) a different SCSI
> > drive attached on the bus, with the same results.  Has anyone any
> > tips for this from a FreeBSD point of view?
> 
> I wouldn't say that dd is the greatest benchmarking tool. You may
> want to try benchmarks/rawio. Also, try monitoring diffferent types
> of transfers to and from another physical disk with iostat. I'm not
> sure what your speed expectations are, but you're running a 7200 RPM
> Ultra Wide disk on an Ultra Wide host adapter; not exactly the
> fastest SCSI technology.

It should go faster than 5MB/sec, though.  Seagate's specs say that
drive should do 14MB/sec max.  UW's top speed is 40MB/sec, so there
shouldn't be any bottlenecks.  

-- 
	Dan Nelson
	dnelson@allantgroup.com



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