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APM Level 128 - Minimum Power Usage Without Stand By (No Spindown)

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khelm

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Feb 10, 2012
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Is APM (Advanced Power Management) Level 128 - Minimum Power Usage Without Stand By (No Spindown) okay to use? I have done enough reading on here to understand that spinning down the drives (Standby Mode) should not be done and understand why, but haven't been able to find anything on if APM Level 128 is okay for the drives or not? I don't want to assume because we all know what happens when we do that! Does the timer setting make a difference for this mode as far as if it's hard on the drive? I guess I should mention that I am using this for a home file server.

I have tried it out on my system with 10 drives, and this level takes the system power consumption from 97 watts to 70 watts (reading from Kill A Watt Meter). It's a nice little power savings and would like to use it especially since I have 4 more drive to add, but I don't want to use it if it will be hard on the drives.

I also have a question about putting it in this mode. It seems to only work if I set the timer for 5 or 10 minutes. Anything higher and it doesn't work. Once it's in Level 128 mode, it does stay there. The SMART service Check Interval is set to 90. I have rebooted when changing these setting to make sure they are set, but it still doesn't work. Just for another test I set the drives to Level 1 - Minium Power Usage with Standby (spindown) and set the timer to 60 minutes and it worked. Yes, I know not to use spindown mode, but this was only a test. Is it possible that the drive doesn't allow for the timer to be set higher than 10 minutes for Level 128 or is there something else that could be preventing it from entering Level 128 that I'm missing? I am using all older Western Digital WD-2002FYPS (RE4-GP) series drive. The specifications are here.

Thanks to all in Advanced!
 

DrKK

FreeNAS Generalissimo
Joined
Oct 15, 2013
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3,630
Well, as you already know, must of us do not use APM/AAM features. As for the timer 5/10 minutes issue, that's been brought up before somewhere in the forum, you can search for it.

There are no free lunches---if there were ways that we could save (as you claim) about 25% of our power consumption without taking unacceptable risks to our hardware and/or file server peformance, all of us would be doing it, and we'd know about it. So even though I cannot quote chapter and verse on this one, I think the sociology of the situation strongly suggests that the small energy savings you are finding is coming at a price that people find unacceptable when they dig into it.
 

cyberjock

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Mar 25, 2012
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19,526
Just to add a little more info, while there is a 'spec' of sorts for the APM/AAM features, the hard drive manufacturer can choose whatever value they want to enable/disable features. So asking if a value of 128 is "okay" or not isn't useful because what may be okay for one model may not be for another. Likewise the effects of the value can change between revisions of the hard drive's internal firmware and hardware.

So yeah.. probably didn't answer your question, but the real answer is to leave that value at the default unless you need to change it unless your intent is to spin down the disks and the other benefits (which you are smart to not want to use anyway). ;)
 
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