[AusNOG] [AUSNOG] Disk wear & Foucault Period

[Paul Wilkins]

1 - The (approx) work done by precession over 5 years = 1800 power cycles
(see above)
2 - So this reduces the work you'll get out of a drive by 1800 power cycles
3 - If we figure a drive is good for 1M restarts, then you'd expect
precession to cause 0.2% of disks to fail over a 5 year lifespan
4 - Whether this shows up in MTBF depends on measurement techniques, and
whether the effect is above the random noise
5 - So if precession is not showing up in MTBF measures, it's a result of
measurement tolerances, and with better measurement techniques, it will

Kind regards

Paul Wilkins

On Thu, 22 Aug 2019 at 13:32, Karl Auer <kauer at biplane.com.au> wrote:

> On 22 Aug 2019, at 10:39 am, Paul Wilkins <paulwilkins369 at gmail.com
> > > > wrote:
> > >
> > > Over a disk's 5 year life, that's about 1800 power cycles. Not
> > > enough to kill a disk, or to even be an obvious problem, but a
> > > hidden and unnecessary drain on disk life and IT budgets.
>
> Except that the precession happens very gradually. You can't compare
> getting punched in the face with the same force delivered as a thousand
> gentle pats.
>
> Regards, K.
>
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