| Bill Todd 2007-02-16, 7:12 pm |
| richard wrote:
....
> HDD failure is every computer user's worst nightmare. The temperature
> issues are obvious to even a novice engineer. So why, oh why, do they
> continue to underdesign these things - not just in external units, but
> inside PC's as well?
The disk manufacturers, at least, don't: the environment for which
their disks are designed is quite publicly specified, and it's hardly
their fault if those who use the disks don't pay attention to it.
Failure rates of (S)ATA units have been studied by users as well as
manufacturers: while the real-world-environment failure rates
encountered by the former (such as the Internet Archive project and the
- I'm sad to say now apparently late - Jim Gray at Microsoft) tend to be
higher than the more-carefully-controlled-environment failure rates
published by the latter, the differences aren't nearly sufficient to
support your allegation that they're 'underdesigned' for their use.
Perhaps you're just unlucky, or unusually hard on your disks, or the
design of the cases you use sucks, or you're using older disks (the
newer ones don't tend to get nearly as hot as you claim when properly
cooled: for the past several years my internal 7200 rpm Seagates have
idled at around 20 degrees C. below their nominal 55 degree C. maximum,
according to S.M.A.R.T., with no special cooling arrangements such as
you describe: the normal influx of air to the front of the drive bays
caused by the PSU fan plus a single auxiliary 80mm. fan is more than
sufficient for them).
Unless the internal air flow misses the drives, you can get a pretty
good idea of how hot disks in external cases are getting by checking
whether the exhaust-fan air feels warm (if not, the flow is probably
adequate to keep the disks cool). You noted that one of your external
cases didn't have a fan, and just acted as a 'blanket'. Maybe, maybe
not: some such cases claim to make good thermal contact with the drive
and conduct heat efficiently to their exteriors (the USB example that I
happen to have here unfortunately doesn't report S.M.A.R.T. attributes
via any of the software I have readily available - anyone know of some
software that might do this?).
In any event, don't presume to generalize from your own experience -
especially given the ease with which you could find broader relevant
information.
....
> Who else has experienced a higher failure rate on external HHD's? Or
> undercooled internals?
Undercooled disks certainly don't live as long - the rule of thumb is
that the life halves for every 15 degree C. rise in operating
temperature (and likely drops far faster if you exceed the nominal
maximum). Of course, external drives may also be prone to more physical
shock during operation than internal drives.
The bottom line is, keep your disks reasonably cool and free from abuse
and they won't disappoint you.
>
> As far as I can tell my only solution for reliable, portable mass storage
> will be to re-engineer a commercial unit to improve it's cooling - but
> void its warranty.
Why not just look around until you find a commercial unit that cools its
disks properly? With external SATA units that should be trivial (no
problem getting the S.M.A.R.T. information there).
- bill
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