[geeks] New 2.5" SCSI HDs???

[Charles Shannon Hendrix]

Thu, 18 Jan 2007 @ 20:57 -0500, Patrick Giagnocavo said:

> On Jan 18, 2007, at 3:54 PM, Charles Shannon Hendrix wrote:
> >
> >
> > True, SATA is an upgrade from IDE, but now that we have made the move,
> > it really makes no sense to keep it around in the future.
> >
> 
> Today I set up a new Linux install for a customer.  A 1U Athlon 1.2 Ghz 
> CPU, with 4x500 SATA drives and a $58 Promise TX4 300 (4-port, 3Gb/s 
> PCI card).
> 
> As part of the install, we mirrored two drives, which Linux will 
> re-sync by copying all the data from one drive to the other drive.
> 
> Using iostat -xk 5 or whatever, I observed 30MB/second reads from drive 
> A to 30MB/second writes to drive B.  CPU usage was under 1% (on a 
> 1.2GHz chip, mind you).
> 
> The fact that you can get that kind of performance, cheaply, is what 
> will keep SATA around.

The biggest difference now (unlike years ago) is that you cannot get low
end drives with SCSI interfaces.  A few years ago, they stopped making
them.

If you take a look at equivalent drives (which are rare), SCSI and SATA
are very close in price.

For example:

	Fujitsu 10K rpm Enterprise drive 36GB, $125
	Western Digital Raptor 10K rpm 36GB, $120

...and the Fujitsu is a better drive.

> If you have ever dealt with OEMs you know that all they care about is 
> price.  SATA was only "allowed" to become a standard, by virtue of the 
> manufacturers of the drive, keeping the price the same as ATA/IDE.
> 
> If SAS adds even 10 cents per system in additional costs, it will not 
> be widespread the way SATA is.

But would it really be more expensive?  Isn't it possible that it would
actually lower costs to have a single interface standard?

Yes, each controller would be more expensive, but you would be making
more controllers overall.

There should also be additional savings by no longer having to split
your R&D and production resources between two different interfaces.

I kind of wonder if costs of both drive systems isn't higher than it
should be because of duplicated effort and other ineffiencies caused by
competing interfaces.


-- 
shannon "AT" widomaker.com -- ["The object of war is not to die for your
country but to make the other bastard die for his." -- General George S.
Patton]