Re: Reasonable maximum package size ?

[Steve McIntyre <steve@einval.com>]

In article <[🔎] 1181593352.3560.6.camel@tomoyo> you write:
>-=-=-=-=-=-
>
>Le lundi 11 juin 2007 à 21:16 +0100, Wouter Verhelst a écrit :
>> The point wasn't that you can't set up a professional RAID array using
>> cheap desktop hard disks; you can, if you really want to, though I
>> wouldn't recommend it. And yes, you're completely free to ignore that
>> particular advise, so long as you don't expect me to become a customer
>> of yours.
>
>You seem to strongly believe the cheap desktop hard disk is different
>from the server hard disk. This is entirely wrong. Apart from 10k and
>15k rpm disks, these are all strictly the same. Only the electronics
>change.

Sorry, but you're utterly wrong. I've worked in the storage industry
for several years and in that time I've spoken to engineers working on
hard drive design and production. There can be significant physical
differences between desktop and enterprise disks including (but not
necessarily limited to) data layout, head assemblies, motors, physical
damping, platter sizes and materials. The underlying principles are
clearly the same, but desktop drives are designed down to a price
using cheaper designs and components wherever possible.

One of the most common mistakes is to make large arrays of cheap
disks. As cheaper disks tend to be less well isolated, vibration and
resonance between the different disks can be a major problem and can
cause very rapid drive failure. Even worse, this is often provoked in
groups such that RAID setups can still fail due to multiple failures.

-- 
Steve McIntyre, Cambridge, UK.                                steve@einval.com
Can't keep my eyes from the circling sky,
Tongue-tied & twisted, Just an earth-bound misfit, I...