spindown.sh

#! /bin/bash
# Check for idle disks and spin them down
# run this from cron every 30 mins
#     */30 * * * * /usr/local/bin/spindown.sh
#  -- craiger, parts taken from Zack Reed

# space separated list of disk wwn names to monitor.
# These should be found in /dev/disk/by-id:
DISKNAMES="wwn-0x5000cca222d23f5f "




export PATH=$PATH:/sbin:/usr/sbin

# Create a file on the ramdisk and cycle it to test for disk activity
( if [ ! -f /dev/shm/1 ] ; then touch /dev/shm/1 /dev/shm/2; fi ; mv /dev/shm/1 /dev/shm/2; cat /proc/diskstats > /dev/shm/1 ) >/dev/null 2>&1

date

# convert disk wwn id's into sdX names because kernel developers
# think they're so clever and randomize sd* names at boot, while most
# userspace tools assume they're static, including /proc/diskstats
for id in $DISKNAMES
do
  SDLIST="$SDLIST `readlink /dev/disk/by-id/$id | cut -d/ -f3`"
done

# Loop through all disks and spin them down if idle.
for disk in $SDLIST
do
  # Check if disk exists
  if [ -e /dev/$disk ]; then
     # Check if disk is currently spinning
     if [ "$(hdparm -C /dev/$disk | grep state)" = " drive state is:  active/idle" ]; then
         #Check if disk has been accessed since last time
         if [ "$(diff /dev/shm/1 /dev/shm/2 | grep $disk )" =  "" ]; then
            echo "Drive $disk is spun up and idle.  Spinning down now."
            hdparm -y /dev/$disk
         else
            echo "Drive $disk is spun up and being accessed.  No change."
         fi
     else
        echo "Drive $disk is already spun down.  No change."
     fi
  else
     echo "Drive $disk not found."   #will never happen
  fi
done