Re: Should I Shut Down External Hard Drives?
- From: Jolly Roger <jollyroger@xxxxxxxxx>
- Date: Mon, 18 Aug 2008 10:15:40 -0500
In article <mirsky-4656CA.21085617082008@xxxxxxxxxxxxxxxx>,
Mirsky <mirsky@xxxxxxxxxx> wrote:
Hi. I own a 24" IMac. I used to keep it on 24-hours a day until I began
worrying about overheating and "image persistence." I now shut it down
I don't see why you would worry about overheating if you allow the
machine to sleep when not in use. When your computer sleeps, unused
components are turned off or in standby mode, which *dramatically*
reduces the heat generated. Also, for LCDs burn-in is very temporary in
comparison with the burn-in to which CRT displays are susceptible. All
you need to do to protect your LCD is configure the screen saver to
start after 5-10 minutes of inactivity, and configure the display to
power off after 15-30 minutes of inactivity.
A quick visit to System Preferences > Energy Saver will allow you to
configure when and how the computer and display go to sleep. No need to
power the machine down at night then. The computer will go to sleep
automatically when not in use, even during the day.
I also have two external firewire drives. I have not been shutting them
down at night because to do so is a bit of a pain in the butt.
However, the drives feel very hot to the touch and I'm worried that they
might overheat at some point and therefore stop working.
Should I be worried?
It's doubtful you should be worried. Hard drives are designed to run
continuously and are also designed to operate in quite hot
conditions.Depending on the type of enclosure housing the drives, the
enclosure may get quite warm to the touch as it channels heat from the
hard drives inside outward. The only way to tell for sure whether a hard
drive might be operating at a temperature higher than recommended is to:
* get the recommended range from the hard drive manufacturer - this is
as easy as looking it up online
* read the actual operating temperature of the hard drive while in
operation within the enclosure - this is harder to do since most
enclosures do not have a sensor to measure heat or display to tell you
the current temperature of the drive(s) inside
I can tell you i have seen hard drives run at temperatures as high as
60+ degrees Celcius, which is around 140 degrees Fahrenheit! A quote
"A 2007 study published by Google suggested very little correlation
between failure rates and either high temperature or activity level;
however, the correlation between manufacturer/model and failure rate was
relatively strong. Google did not publish the manufacturer's names along
with their respective failure rates. While several S.M.A.R.T. parameters
have an impact on failure probability, a large fraction of failed drives
do not produce predictive S.M.A.R.T. parameters. S.M.A.R.T. parameters
alone may not be useful for predicting individual drive failures.
A common misconception is that a colder hard drive will last longer than
a hotter hard drive. The Google study seems to imply the reverse --
"lower temperatures are associated with higher failure rates". Hard
drives with S.M.A.R.T.-reported average temperatures below 27 C had
failure rates worse than hard drives with the highest reported average
temperature of 50 C, failure rates at least twice as high as the optimum
S.M.A.R.T.-reported temperature range of 36 C to 47 C. Possible
explanation of this observation may be based on the fact that failed
drives were stopped yet not removed from the continuing study, thus
contributing low temperature readings to the statistical distribution of
the failed population."
All this says to me you probably have nothing to worry about with your
external drives as well.
Mac OS X, being Unix-based, is designed and configured from the factory
to run certain cleanup operations in the middle of the night (usually at
3 AM unless you've actively changed it). These operations mostly do log
rollover and some other things to help your computer run optimally. If
you shut down your computer every night, some versions of Mac OS X will
fail to do these operations.
Send responses to the relevant news group rather than to me, as
E-mail sent to this address may be devoured by my very hungry SPAM
filter. Due to Google's refusal to prevent spammers from posting
messages through their servers, I often ignore posts from Google
Groups. Use a real news client if you want me to see your posts.
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- From: Mirsky
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