Date: Tue, 5 Nov 1996 16:48:59 -0800 (PST) From: Veggy Vinny <richardc@CSUA.Berkeley.EDU> To: Joe Greco <jgreco@brasil.moneng.mei.com> Cc: michaelv@MindBender.serv.net, isp@FreeBSD.org, chad@gaianet.net, johnnyu@accessus.net, mario1@PrimeNet.Com Subject: Re: /usr/obj size Message-ID: <Pine.PTX.3.95.961105164539.4315f-100000@soda.CSUA.Berkeley.EDU> In-Reply-To: <199611052318.RAA07444@brasil.moneng.mei.com>
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On Tue, 5 Nov 1996, Joe Greco wrote:
> > 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.)
Actually, the smaller drives are cheaper now. But I guess it
depends on how much room you have left for your computer's pci slots for
controller cards as well.
> > > > 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.
Hmmm, where can I get more info on how to do CCD under FreeBSD?
Vince
GaiaNet Corporation - Unix Networking Operations - GUS Mailing Lists Admin
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