[Beowulf] Re: Cooling vs HW replacement

[David Mathog]

> "Robert G. Brown" <rgb at phy.duke.edu> wrote:


> 
> I mean, disk is SO cheap at less than $1/GB. 

That's certainly true for consumer grade disks.  "Enterprise"
or "Server" grade disks still cost a lot more than that.  For
instance Maxtor ultra320 drives and Seagate Cheetah drives
are both about $4-5/GB.   The Western Digital Raptor
SATA disks are also claimed to be reliable, and are
again, in the $4-5/GB range. (Ie, it isn't just SCSI
that makes server disks expensive.)

Sure, you can RAID the cheaper ATA/SATA disks and
replace them as they fail, but if you're really
working them hard, the word from the storage lists is that
they will indeed fail.  (Let Google be your friend.)

Note that our compute nodes' disks are just Western Digital
ATA drives, and we've only had one failure out of 20 in 2 years.
But we don't push those drives very hard. Under normal conditions
they are only used to boot the OS or occasionaly to a new
load a database into memory.  The disk server uses SCSI disks
and is pushed much harder.

Regards,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech