#!/bin/bash
# Check for idle disks and spin them down
# Some Harddrives not working to spindwon with hdparm -B oder -S commands.
# But hdparm -y direct work. So that a script for that Harddrives.
# http://linuxwiki.de/hdparm
#
# Installation:
# ---------------
# For this script hdparm must be installed, but not configured!
# Only a apm=255 is maybe needed in the hdparm.conf for the Drive.
#
# Installation:
# Put it to /usr/local/bin/disk_spindown.sh
# Set the Permissons sudo chmod 744 /usr/local/bin/disk_spindown.sh
# Startup: we put a new line in /etc/rc.local for systemwide start.
# /usr/local/bin/disk_spindown.sh & >/dev/null
# exit 0
#
# Now you can reboot the pc, for activate or to activate a change.
#
# Western Digital Green Harddrives (mostly not suitable with hdparm -S or -B)
# ---------------------------------------------------------------------------
# Modern Western Digital "Green" Drives include the Intellipark feature that stops the disk when not in use.
# Unfortunately, the default timer setting is not perfect on linux/unix systems, including many NAS,
# and leads to a dramatic increase of the Load Cycle Count value (SMART attribute #193).
# Please deactivat it with http://idle3-tools.sourceforge.net/ (normally in the Distro)
#
# get the Info: idle3ctl -g /dev/sd(x)
# disabling :   idle3ctl -d /dev/sd(x)
# The idle3 timer seems to be a power on only setting. That means that the drive needs to be powered OFF and then ON to use the new setting.
# I turn off the Computer, plug the power off and push the start button, for a short while the fan go's on. All power it out. 
# Or turn off for few minutes to take the effect.

# Where is your Ramdrive? 
# Check it out with  df -h or mount command.
# Possible Values Examples: /dev/shm , /run/shm 
ramdrive=/run/shm

# The Spindwon Time in Seconds
# The Raktion done in $spindowntime maximum of 2 times. Depending build by the script. Protects for the cpu load. 
spindowntime=1200

# Wich disk are handled 
diskvolumes="b c d e f g h i j k"

# Build onece the tempfiles 
if [ ! -f $ramdrive/diskstate1 ]; then touch $ramdrive/diskstate1;fi 
if [ ! -f $ramdrive/diskstate2 ]; then touch $ramdrive/diskstate2;fi

# Here we go... 
while [ true ] ; do

# cycle it to test for activity 
mv $ramdrive/diskstate1 $ramdrive/diskstate2 
cat /proc/diskstats > $ramdrive/diskstate1

# Loop through all array disks and spin down idle disks. 
for disk in $diskvolumes 
do
   if [ "$(diff $ramdrive/diskstate1 $ramdrive/diskstate2 | grep sd$disk )" =  "" ] ; then hdparm -y /dev/sd$disk >/dev/null 2>&1; fi

done 

# Wait
sleep $spindowntime
done
exit 0