Spinning down a WD20EARS “Green” drive

Ok, this is a pretty utilitarian post.  I did finally get my 18W Server up and running; in fact, it’s serving this post!  But I can’t really get to 18W unless the 2x 2T WD20EARS [amzn] drives I have in it for media storage spin down when not in use.

And I had a heck of a time making that work.  hdparm -y would quickly spin them down, but using hdparm -S to set an idle timeout seemed to have no effect; I had been trying to use hdparm -S 241 to set a 30 minute spindown time, and I had no luck whatsoever.  With the drives spinning, the server used more like 30W.

Mostly through trial and error, I found out that if you set a lower spindown timeout, i.e. hdparm -S 3, the drive will spin down in 10 minutes.  So unlike most drives which follow the timeouts as specified in the hdparm manpage, this one seems to spin down in 10 minutes for low -S values, and never for higher values.  I don’t know what the threshold is, but for now, hdparm -S 3 is doing the trick for me.  After doing this, the drives finally managed to be idle most of the time, when not serving up media:

I also used the idle3-tools to turn off the idle3 behavior and save the drives from the massive load/unload cycles; I don’t know if that’s warranted or not, but I did it anyway.

On a related note: The Western Digital Red [amzn] “NAS-optimized” drives might actually use a bit less power than even the “Green” drives.  They use 4.4W (vs 5.3W on the Green) for read/write, 4.1W (vs. 5.5W) for idle, and 0.6W (vs. 0.7W) for standby/sleep.  (Comparing to the WD20EFRX and WD20EZRX models here).  If one of the Green drives in the mirror goes, I might consider replacing it with a Red.

10 thoughts on “Spinning down a WD20EARS “Green” drive

  1. Interesting… I was considering one of the WD Green drives for my next system rebuild, but from what you say a Red might be worth looking at.

    • I use a simple bash script like this to feed mrtg:



      /sbin/hdparm -C $DRIVE1 | grep -q active && echo “1” || echo “0”
      /sbin/hdparm -C $DRIVE2 | grep -q active && echo “1” || echo “0”
      /usr/bin/uptime | uptime | sed “s/.*up \(.*\),.*users.*/\1/”

      and it yields:

      # smart-spin-mrtg.sh
      31 days, 20:49

  2. Thank you for the tip! Same behavior with a wd40ezrx, the drive will spin down in 10 minutes using hdparm -S 3.

  3. i have a WD RED (WD20EFRX) here. same problem. setting hdparm -s to 1, 2 or 3 seems to enable standby after 10 minutes.

    glad i found your blog after after fiddling around for two hours.

    • I just run a little script from mrtg:



      /sbin/hdparm -C $DRIVE1 | grep -q active && echo "1" || echo "0"
      /sbin/hdparm -C $DRIVE2 | grep -q active && echo "1" || echo "0"
      /usr/bin/uptime | uptime | sed "s/.*up \(.*\),.*users.*/\1/"

  4. I have 3 WD Green drives:
    WD15EADS – 1.5TB 32MB Cache – Firmware 01.00A01
    WD10EACS – 1.0TB 16MB Cache – Firmware 01.01A01
    WD10EAVS – 1.0TB 8MB Cache – Firmware 01.01A01

    All drives spin down immediately with the hdparm -Y command.
    All drives does not behave as expected using the hdparm -S command to set the spin down time.

    For the WD15EADS, hdparm -S 3 /dev/sdx, makes the drive spin down after 10 min.
    For the WD10EAVS, hdparm -S 3 /dev/sdx, makes the drive spin down after about 15-20 min. (Haven’t timed it accurately, but it works consistently)

    However, the WD10EACS does not spin down at all. What can cause this? The WD10EACS only differs from the WD10EAVS by the amount of cache. It even has the same firmware revision.

    All the drives are empty, and I’m certain I don’t have anything accessing the drives which can keep them active.

    BTW: For all drives the dreaded idle3 timer is disabled.
    Apparently none of the drives support Advanced Power Management (hdparm -B /dev/sdx gives APM_level = not supported)

  5. Thank you for sharing your findings.
    I can confirm your approach finally got my Western Digital Caviar (500GB) to spin down automatically, running on Ubuntu. The drive is:

    WDC WD5000AAKS-22TMA0

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