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Should I Shut Down External Hard Drives?

Message #1 - Posted 2008/08/18 - Mirsky

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 at night.

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?

Thanks

Mirsky

Message #2 - Posted 2008/08/18 - Heli

Previously, Mirsky 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 at night.

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?

Thanks

Mirsky

Yes, I would shut them down, certainly in this case. I only turn them on when I backup and off again after that.

Message #3 - Posted 2008/08/18 - Jolly Roger

Previously, Mirsky 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 at night.

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 from Wikipedia:

"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."

<http://en.wikipedia.org/wiki/Hard_disk>

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.

JR

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