Spindown SAS disks

So, in my previous article, I was struggling to get a new SAS disk to spin up.  Now that I have that working, I want to get it to go into standby (spindown) when it’s idle for a while.  I previously provided directions to use hdparm to spindown disks.  Although hdparm works with SATA disks, SAS disks are a different beast.  To work with them you need to use sdparm.

sudo -i
apt-get install sdparm -y

Once it is installed, you can use this code to view the current spindown parameters (my disk is /dev/sdp or use /dev/disk/by-id/).

sdparm --flexible -6 -l --get SCT /dev/sdp
sdparm --flexible -6 -l --get STANDBY /dev/sdp

You may get output that looks like this…

STANDBY     0  [cha: y, def:  1, sav:  1]
SCT       4294967286  [cha: y, def:9000, sav:9000]

I this case, STANDBY = 0 means that the disk will never spindown. So, let’s change that…

sdparm --flexible -6 -l --set SCT=18000 /dev/sdp
sdparm --flexible -6 -l --set STANDBY=1 /dev/sdp

The first option enables standby (spindown), and the second sets the timer. The SCT number is equal to 100ms. So, 18000 = 30 minutes.

And, that’s it. These values should be saved to your disk and even be portable between systems. If you do run across a funky disk that doesn’t retain these values through a reboot, you can always add a line like this to /etc/rc.local

sdparm --flexible -6 -l --set SCT=18000 --set STANDBY=1 /dev/sdp


I love learning new things and trying out the latest technology.

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