With the original IBM-PC XT's it was risky to merely turn the unit back on.
The drives had terribly short lifespans... and many problems. Thus we have
some new coral reefs thanks to IBM...
New computer drives are far more reliable with somewhat amazing MTBF
ratings...
thirty years or more of continuous operation in some cases...
HOWEVER there is a phenomena called "striction" which can still affect these
drives.
Striction occurs because microscopic particulates are released in normal
operation and are present in the air. Over time some of this material can
adversely affect the bearings on the drive mechanism (let's not go into head
crashes...).
As a result the drive requires more torque to spin up. At some point a magic
line is crossed, wherein the drive motor mechanism can no longer supply
enough torque to even begin to spin such a drive up.
This is notable because the system may fail to boot once or twice, then run
fine for long periods of time before this happens again...
Interestingly enough, often "helping" the drive by spinning the drive in
your hand while it powers up can sometimes free a "stuck" drive without
harming the data therein.
Anyways striction is often the death knell for continuously run units that
otherwise have no other problems. Ironically, striction is caused by run
time factors... more likely as the drive is kept on.
Now consider damage caused by power spikes, lightning, etc...
The longer a unit is running, the more exposed it is to problems. Like a car
that you keep in the garage whenever it is not in use, having the computer
off reduces exposure.
Likewise it's not a good idea to continually subject your car engine to cold
starts...
Fans are also notoriously "weak". Ball bearing fans will someday force the
end of western civilization...
So... the 8 hour rule, applies pretty well... If you will use it again
within 8 hours, leave it on. Otherwise turn it off... unless of course it's
working on the SETI project...
-JMS
----- Original Message -----
From: Eric Livingston <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, November 03, 1999 10:28 PM
Subject: To Power down or not to Power down, that is the question...
> I'm sure this has been hashed out many times before, but I can't find
> anything in the HOWTOs or other documentation on this issue.
>
> I've got a relatively old machine (P90, with a 1Gig drive) that's in use
> now as my home server. Since I'm at work most of the day, and sleeping
> most of the night (well, not most I guess...) I'm using the machine
> perhaps 4-5 hours a day at best, many times only 1-2 hours a day.
>
> In this scenario, is it better to power the machine down for the
> night/workday most of the time, and just power it up for a few hours a
> day, or should I leave it on all the time?
>
> I'm aware of the processes Linux needs to run periodically at night to
> remain up-to-date (like makewhatis, etc), so I'd leave it on overnight
> perhaps once a week for that purpose.
>
> Really it gets down to the longevity of the hard drive and power supply,
> the theory being that the fans/drive motors take the most abuse during
> spinup and spindown relative to remaining at a constant speed, so at some
> point the wear and tear accumulated by always leaving them on is less
> than it would be subjecting them to daily power-ups and power-downs.
>
> I've heard that the tradeoff is at about 8 hours or so - that is, if the
> machine will be used 8 or more hours a day then it's better just to leave
> it on all the time, whereas lesser usage would indicate turning it off
> during downtime.
>
> Any thoughts?
>
> Thanks,
> Eric.
>
>
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