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 <[email protected]> wrote: > On 22 Aug 2019, at 10:39 am, Paul Wilkins <[email protected] > > > > 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. > > -- > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Karl Auer ([email protected]) > http://www.biplane.com.au/kauer > http://twitter.com/kauer389 > > GPG fingerprint: 8D08 9CAA 649A AFEF E862 062A 2E97 42D4 A2A0 616D > Old fingerprint: A0CD 28F0 10BE FC21 C57C 67C1 19A6 83A4 9B0B 1D75 > > > _______________________________________________ > AusNOG mailing list > [email protected] > http://lists.ausnog.net/mailman/listinfo/ausnog >
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