My WD Green WD15EARS refuses to spin down using the hdparm spindown timer,
however it will spin down manually using
hdparm -y /dev/sdX.
The following script run via cron uses
/sys disk stats and a status file
to check if the disk has been used and force the spindown.
This is an update to a script found here: http://superuser.com/questions/651880/force-spin-down-of-external-hard-drive-on-linux-raspberry-pi
I have updated it to work with multiple drives placed in an array, and