Date: Tue, 5 Nov 1996 17:18:39 -0600 (CST) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: richardc@CSUA.Berkeley.EDU (Veggy Vinny) Cc: jgreco@brasil.moneng.mei.com, michaelv@MindBender.serv.net, isp@FreeBSD.org, chad@gaianet.net, johnnyu@accessus.net, mario1@PrimeNet.Com Subject: Re: /usr/obj size Message-ID: <199611052318.RAA07444@brasil.moneng.mei.com> In-Reply-To: <Pine.PTX.3.95.961105132323.13095Q-100000@soda.CSUA.Berkeley.EDU> from "Veggy Vinny" at Nov 5, 96 01:27:07 pm
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> On Tue, 5 Nov 1996, Joe Greco wrote:
>
> > > The reason I keep saying 2GB is because that seems to be the current
> > > "sweet spot" where the price per gigabyte is lowest, and the
> > > performanc is at least "good".
> >
> > For price, 2GB is your ticket. For performance, 1GB is (I have recently
> > paid the "premium" to get a dozen and a half ST-31055N's... ouch... it
> > hurts, but you get almost double the throughput for having spent about
> > 30% more than the 2GB drives would have cost).
>
> Hmmm, speaking about 2 GIG drives, the new Barracuda's are cheaper
> than the ST32550N, I wonder if any performance is sacraficed since it has
> half the cache but come in both UltraSCSI and UltraSCSI Wide versions.
> Never thought about it but 5 2 GIG drives are cheaper than a single 9 gig
> drive, I always thought the bigger the drive, the less the cost per
> megabyte.
Think about this:
Two drives each with half the cache of a larger drive have the same amount
of cache, total, as the larger drive.
Two drives have twice the heads of a larger drive.
Two drives do not cost too much more than the larger drive. Let us say it
costs 30% more.
If you buy the larger drive and find it is too slow, you buy the two
smaller drives and then you have spent 130% more. (But you have an
additional drive.)
> > > Of course 7200RPM drives are faster. But, if you can buy an extra
> > > drive or two, and put that in the stripe set, with the money you save
> > > by going 5400RPM, that extra drive might just make up the difference
> > > in speed. So, to say it the other way around: no, you don't need
> > > 7200RPM drives.
> >
> > Yes. I will put a two-disk stripe of a pair of ST-31055N Hawk-2 drives
> > (9ms, 5400RPM, etc) up against a single ST-32550N Barracuda (8ms, 7200RPM)
> > any day and beat it by a fair margin. And relatively speaking, with the
> > 32550N's hovering around $650 and 31055N's around $320, tell me what
> > makes more sense to do :-)
> >
> > But I will grant that the 32155N's, in the low 5's are attractive too.
>
> Hmmm, I know I just asked this. but how does striping work and is
> it only for SCSI drives?
Striping ("CCD") works on general disk devices. I have never tried it on
non-SCSI drives or with non-PCI controllers.
... JG
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