On Mon, 31 Jul 2000, Russell King wrote:
> Michael Bacarella writes:
> > Why is this even desirable?
>
> >From what I've read, most of the cheaper "desktop" drives aren't designed
> to run for ever, unlike those for servers (or IBM would have you believe
> this). However, there are two figures from the drive spec that come
> into play - the MTBF and the number of spin up/down cycles that the
> drive can withstand. (With marketing of hard drives these days as it
> is, do you think you can really find the truth about this out there? ;()
This is why ATA 7200 RPM drives are based on HDA's that are SCSI2.
Now would you call a 7200 RPM SCSI2 drive junk?
> If anyone does know the definitive answer, I'd be interested to know!
Not all knowing or "the definitive answer" but will share what I do.
> There are also the environmental (noise) reasons as well.
> > Wouldn't you want the drives to just spin forever? I always understood
> > that spinning something down and then spinning it back up is what causes
> > them to degrade/die. The analogy would be that a car that runs it's engine
> > for 10 years straight never needs major repairs, whereas one that is
> > turned on, driven, turned off, repeat, will be slowly destroyed.
Some truth here......but you have determine your usage model.
Last check a few years back was each power-up or spinup from stop is about
10 hours of continious running.
So in an environment of 8-10-hour business days for 5 days per week.
Power on plus 10-hour day is about 20 hours.
20*5 << 7*24 or it costs you 68-78 hours of extra usage against the MTBF,
per week or 3/4 of a business week.
Remember that you have to float the heads and sticking can be an issue for
stopping. Also with accoustic management or spindle throttles you can
achieve different results. The assumption above is that we are running at
max RPM always.
Best case is to place mount drives (regardless of type) in
anti-shock/vibration racks on an individual bases. Even spindle sync will
generate beat-harmonics that moments of inertia frown upon. Remeber that
75-100 G is easy to do with impulse.
Cheers,
Andre Hedrick
The Linux ATA/IDE guy
Please correct were I am inaccurate, please, anyone.
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This archive was generated by hypermail 2b29 : Mon Jul 31 2000 - 21:00:32 EST