[5344] in linux-scsi channel archive
Re: Dumb question: Which is "better" SCSI or IDE disks?
daemon@ATHENA.MIT.EDU (C S Hendrix)
Mon Dec 7 20:40:59 1998
To: linux-scsi@vger.rutgers.edu, linux-kernel@vger.rutgers.edu
Reply-To: shendrix@escape.widomaker.com
In-reply-to: Your message of "Mon, 07 Dec 1998 02:27:16 EST."
<Pine.LNX.4.04.9812070215060.3437-100000@localhost>
Date: Mon, 07 Dec 1998 14:13:02 -0500
From: C S Hendrix <shendrix@escape.widomaker.com>
In message <Pine.LNX.4.04.9812070215060.3437-100000@localhost>, Christopher Smi
th writes:
> This is just a case of silly benchmarking. Do you really believe that IDE
> is 4x faster than SCSI? All those big server vendors must be idiots eh?
This is the one point that should settle the argument, but seems
to have no effect.
> Well, based on this, your IDE drive is so fast it ever outperforms RAM!
> ;-) (You are copying ~9 MB through a controller with 32 MB of cache.) My
> suspicion is that your DPT RAID-1 controller with 32 MB cache is setup
> with write caching disabled, as is the case for your SCSI hard disks. This
> is one area where SCSI performance typically lags behind that of IDE,
> because SCSI hard disk vendors typically setup their caches to not do
> write caching by default (this can typically be changed, however). This is
I noticed this was an option with the scsi tools under Linux, and
I was wondering if it was prudent for me to turn on write cache on
my drives. All of them support the option.
> Based on the information you've provided, it seems apparent that you are
> testing with 2 different drives. Of course, you are also comparing two
> entirely different OS's (ok, they're both Unixes, but SCO Open server is a
> pig, and we all know it). On top of that you're dealing with two totally
> different filesystems. I wonder if you are even using the same hardware
> (CPU/memory/etc). What exactly do you think this benchmark proves?
My DPT based system (Seagate Hawks, fast-wide) did the test in 0.65
seconds. Big hairy deal. I have no idea when the data actually
made it to the disk. The same test test was 1.5 seconds to my very
slow IDE Zip drive... :)
--
Shannon - shendrix@widomaker.com - InfiNet?
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"We are all of us in the gutter, some of us looking at the stars." --
Alexander Pope
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