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Is there any way how to determine whether some drive is sleeping without occasionally waking it up? I have tried hdparm -C and smartctl -i but both of them actually wake it up when its already sleeping.

I need to set up a script that regularly checks the drive states and sets them asleep at certain times in case they are not sleeping already. (In fact that calling hdparm -Y on a sleeping drive actually wakes it up!).

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I imagine that, since you're polling the drive's firmware, it needs to wake up to activate that. – user3914 May 31 '11 at 5:07
up vote 4 down vote accepted

Try using standby (hadparm -y) mode instead of sleep (hdparm -Y). In this mode issuing hdparm -C or smartctl --nocheck standby -i won't wake up drive.

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What's the exact difference between standby mode and sleep mode? In terms of power consumption. – NumberFour Jun 2 '11 at 14:57
I don't know but I suspect that difference is minimal because in both modes drive is spun down. – AlexD Jun 2 '11 at 15:56

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