HD Idle Manual Spin Down

spindown.sh

#!/bin/bash
# This script looks for recent disk access, and if nothing has changed, puts /dev/disk/by-id/${drive} into spindown mode.
#
# Array of problem drives this script looks at, listed by id (from /dev/disk/by-id/):
drives=(
    "ata-WDC_WD15EARS-<ID>"
    "ata-<OTHER_DRIVE>-<ID>"
)

current=`date`
DEBUG="false"

for device_id in ${drives[*]}
do
    device=`readlink -nf /dev/disk/by-id/${device_id}`
    d=`basename ${device}`
    filename="/tmp/diskaccess-${d}.status"
    stat_new=`cat /sys/block/${d}/stat | tr -dc "[:digit:]"`
    if [ -f "${filename}" ]; then
        stat_old=`cat ${filename} | tr -dc "[:digit:]"`
        if [ "${stat_old}" == "${stat_new}" ]; then
            if [ ${DEBUG} == "true" ]; then
                echo ${current} "- Executing: hdparm -C /dev/${d} | grep -c 'drive state is:  standby'" >> /tmp/diskaccess.log
                hdparm=`hdparm -C /dev/${d}`
                echo ${current} "- ${hdparm}" >> /tmp/diskaccess.log
            fi
            match=`hdparm -C /dev/${d} | grep -c "drive state is:  standby"`
            if [ "${match}" == "1" ]; then
                echo ${current} "- Drive /dev/${d} already in standby; leaving current state" >> /tmp/diskaccess.log
            else
                echo ${current} "- Drive /dev/${d} hasn't been used; spinning down" >> /tmp/diskaccess.log
                hdparm -y /dev/${d} > /dev/null
            fi
        else
            echo ${current} "- Drive /dev/${d} has been used..." >> /tmp/diskaccess.log
            echo ${stat_new} > ${filename}
        fi
    else
        echo ${current} "- ${filename} file does not exist; creating it now." >> /tmp/diskaccess.log
        echo ${stat_new} > ${filename}
    fi
done

WD_Green_spin_down.md

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 indexed by id so that any drive letter changes across reboots do not end up with us attempting to sleep different drives.