Re: Dumb question: Which is "better" SCSI or IDE disks?

Rik van Riel (H.H.vanRiel@phys.uu.nl)
Mon, 7 Dec 1998 14:28:41 +0100 (CET)


On Mon, 7 Dec 1998, Leonard Zhang System Administrator ISD RVIB wrote:
> On Sun, 6 Dec 1998, Alan Cox wrote:
>
> > > I think currently spinning SCSI hard disks on the world, either in servers
> > > or workstation, either in Unix/Linux or NT, is 50-pin old guys, no DPT disk
> >
> > And as my stats showed for real work even old 5400 rpm fast scsi on a
> > now discontinued adapter (the BT946) beats current UDMA IDE for real world
> > compiles. You "think". I've "measured"
>
> Open server 5.0.4p, DPT RAID-1, 32 MB cache, PCI, 4.2 GB (A cable)
>
> copy 9,177 K in 9 seconds.
>
> Red hat 4.2, 8 GB IDE
>
> copy 9,397 K in 2 seconds.
>
> both run in shell script.

Sigh...

You benchmarked two different drives under different OSes on
different machines and try to extend those results to a general
performance difference between SCSI and IDE...

(sounds rather rediculous when viewed this way, doesn't it)

This is simply not a proper benchmark for the results you want
to achieve. If you want to prove that IDE gives you more bang
for the buck, you should get a machine and use a SCSI subsystem
and an IDE subsystem which cost about the same amount of money
_in that same machine_ and test _using the same OS_ and the
_same workload_. Furthermore, you should be using a realistic
workload and not one that's been tuned to give the result you
want.

regards,

Rik -- the flu hits, the flu hits, the flu hits -- MORE
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