[gpfsug-discuss] green drives

[Jonathan Buzzard]

On Tue, 2013-07-09 at 15:49 +0100, orlando.richards at ed.ac.uk wrote:
> On Tue, 9 Jul 2013, Pete Smith wrote:
> 
> > Even more mental ... anyone using green drives in their lowest HD tier?
> >
> > I've used them in a Nexsan with MAID capability, for nearline, and
> > they were fine for this purpose, but I wouldn't expect them to sit
> > happily in GPFS.
> >
> > Happy to be confirmed wrong in my suspicions.
> >
> 
> By "green" - do you mean the 5400rpm drives? Or something else 
> (spin-down?)?
> 
> If 5400rpm - I can't think of a reason they wouldn't perform to 
> expectations in GPFS. Naturally, you'd want to keep your metadata off them 
> - and use them for sequential activity if possible (put large files on 
> them).
> 

You also I think need to make sure you are using "enterprise" versions
of such drives. However I don't believe there are "enterprise" versions
of the 5400rpm drive variants, therefore using them would be in my
personal experience as dum as hell.

Another point to bear in mind is you will save a lot less power than you
might imagine. For example a Seagate Desktop HDD.15 4TB drive is 7.5W
read/write, 5W idle and the name gives it away. While a Seagate
Constellation ES.3 4TB drive is 11.3W read/write and 6.7W idle and
enterprise rated.

To make those numbers more meaningful for ~90TB or usable disk space
doing three RAID6's of 8D+2P you will save ~120W. Is that really worth
it?

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.