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Old 2002-08-16, 19:07   #1
outlnder
 
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Default Keeping the Heat down at Home

I have a home farm of 15 machines. Most are TBirds, so you can imagine the heat problem I have. I have found a way to eliminate some of the heat and as a benefit have cut down on noise and hopefully electricity usage.

Lumly, one of our more intelligent crunchers, stated that he sets his "Minutes between disk writes" in the "Options" > "Preferences" section to 720 minutes, or 12 hours. He said he also powers down his hard drive after 3 minutes because he can't stand the noise.

I thought that this might be able to benefit me a bit. I set my disk writes to 720 minutes and powered down my hard drives after 3 minutes and added my monitor to power down after 1 minute.

Well, low and behold, within 30 minutes I could feel a temperture drop. And the noise was not quite so loud either. Now it's just a matter of time to see if there will be a significant electricity usage drop.

If anyone sees any problems with this setup, please reply. I'd hate to lose all this crunching time because of a Windows failure I know nothing about.
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Old 2002-08-16, 20:42   #2
maxscribe
 
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The critical thing is to tell the machine to turn the drives off! Once the drive spins up and written to you want it off again pronto. Think you know how to do that...
:D

One warm quiet disk multiplied by 15 is lots of background noise and heat.

Down side is losing 12 hours of crunching if there's a problem!
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Old 2002-08-16, 21:22   #3
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Eek! On the hot seat.

Just a few things to consider. There is always a trade off when doing these things.

There is, of course, the possibility of losing up to 12 hours of work should something hang or there be a power outage.

Another thing to consider is the wear and tear on the harddrives. This is why I chose an astronomical 12 hours. I could have chosen 2 hours, but that would be at least 12 spin-ups per day. If I had 15 computers spinning up every 2 hours it would still drive me round the bend. :) and since GIMPS work units takes days to weeks each, 12 hours is not that large a loss.

My harddrives would spin-up when connecting for the daily PrimeNET update, so I figgured 2 spin-ups per day was good. If you have a system whereby you do automated backups of your Prime95 directories into a center harddrive, then you'll end up with 3 per day.

You will have problems with this setup on a computer that doesn't have much RAM. Any pagefile swapping will cause the harddrive to spin-up. This is what happened to my 32MB P1-200.

Enough rambling. :D
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Old 2002-08-16, 22:06   #4
Prime95
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Quote:
Originally Posted by Lumly
If you have a system whereby you do automated backups of your Prime95 directories into a center harddrive, then you'll end up with 3 per day.
Plus two writes per day updating the RollingAverage in local.ini
(actually many more than 2 if using v21.4).
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Old 2002-08-16, 22:11   #5
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Modern hard drives are rated for at least 40,000 power-on cycles... If you powered down every hour it would take you a long time to exceed this... Somewhere around 4 years I think...
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Old 2002-08-16, 22:13   #6
Digital Concepts
 
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What is the activity for later releases?

Is there a way to configure the time between all writes or could local.ini be timed to occur with data saves?
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Old 2002-08-16, 22:41   #7
Prime95
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Quote:
Originally Posted by Digital Concepts
What is the activity for later releases?

Is there a way to configure the time between all writes or could local.ini be timed to occur with data saves?
Unfortunately, no. I'll add the suggestion to my wish list.

v21 wrote to local.ini every 65536 iterations. v22 updates the rolling average twice a day.
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Old 2002-08-16, 23:52   #8
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Quote:
Originally Posted by Xyzzy
Modern hard drives are rated for at least 40,000 power-on cycles... If you powered down every hour it would take you a long time to exceed this... Somewhere around 4 years I think...
The drives I'm using for Lumly01 and Lumly03 are roughly that age.

Time to pull out my dusty copy of Delphi and make that autobackup app.
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Old 2002-08-17, 00:21   #9
outlnder
 
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I will be upgrading to 22.8 tonight.

I must say the heat difference is so immense, I can actually sit next to my farm and work on my computer. Last week I had a 21" fan blowing full on me and was still sweating like a pig.

Lumly, you are a life saver. Let's hope the power saving is good.

I did remember why I changed all my drives and monitor to be always on 3 years ago, Win98 had a problem with not waking up. So far, I have not had this problem. But it's only been one day.
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Old 2002-08-17, 13:27   #10
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It's hot here in the UK as well (my home farm is a mere 4 machines but it adds up) so the gerbil (real) cage has now got a pair of AT power supply fans keeping it cool and sweet! My P95 machines are named various shades of 'gerbil' so only fair to keep their namesakes in the best of climates.
Frivolous but it's hot and saturday and quiet and I'm bored and... :)
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Old 2002-08-17, 13:48   #11
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Quote:
Originally Posted by outlnder
Let's hope the power saving is good.
Most newer hard drives consume around 6 watts or so idle... So, over a month's time, each hard drive will cost you around 35 cents... This is if you pay 8ยข per kilowatt hour...

Here is the formula...

24 * 30.5 * 6 / 1000 * 8

24 = hours in a day
30.5 = days in a month
6 = idle watts
1000 = conversion from watts to kilowatts
8 = cost in cents per kilowatt hour

Of course, I bet you pay more per kilowatt hour in California...
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