sas-spindown.sh

#!/usr/bin/env bash

# sas-spindown.sh by David Froehlich <dfroe@gmx.de>
#
# Uses iostat to spindown sas devices which cannot be
# controlled by 'camcontrol idle'.
#


# List of all monitored devices.
DEVICES=""

# The following command retrieves this list by calling camcontrol
# and filtering all devices connected to the first scsi bus
# (i.e. the lsi sas controller without any onboard sata devices).
DEVICES="$DEVICES
`camcontrol devlist | grep 'scbus[0] target [1-9][0-9]*' \
                    | grep -o 'da[0-9][0-9]*'`"

# Uncomment to also add all ahci devices.
#DEVICES="$DEVICES
#`camcontrol devlist | grep -o 'ada[0-9][0-9]*'`"


# Timeout in minutes.
# A spindown command will be sent to all monitored devices
# which had no activity during the last n minutes.
TIMEOUT=30


# Path to some binary which should normally be within $PATH.
IOSTAT="`which iostat`"
CAMCONTROL="`which camcontrol`"


#
# Do not edit any lines below unless you know what you are doing!
#


# Check for valid device list.
if [ -z "$DEVICES" ] ; then
  echo "Error: Device list is empty!" >&2
  exit 1
fi

# Check for valid device list.
if ! printf "%d" "$TIMEOUT" >/dev/null 2>&1 ; then
  echo "Error: Timeout \"$TIMEOUT\" is not a number!" >&2
  exit 1
fi

# Check for required binaries.
for i in IOSTAT CAMCONTROL ; do
  eval bin=\$$i
  if ! [ -x "$bin" ] ; then
    echo "Error: $i binary \"$bin\" is not executable!" >&2
    exit 1
  fi
done

# Create and initialize internal variables $INACTIVITY_<device>
# containing the number of minutes a device has been inactive.
for dev in $DEVICES ; do
  eval INACTIVITY_$dev=0
done

# Increment the configured timeout by one.
# This is a fix because the check whether a device has reached
# the threshold is performed at the beginning of each iostat run
# before the statistics are parsed (and not after).
TIMEOUT=$(($TIMEOUT+1))

# Try to determine the first column of the first and second line
# of the iostat headlines.
# These will be used to separate multiple iostat runs.
IOSTAT_COLUMNS="`$IOSTAT -d -I -x | head -n 2 | \
while read first_column remaining_columns
do
echo $first_column
done`"
for col in $IOSTAT_COLUMNS ; do
  if [ -z "$IOSTAT_1stLINE_1stCOLUMN" ] ; then
    IOSTAT_1stLINE_1stCOLUMN="$col"
  elif [ -z "$IOSTAT_2ndLINE_1stCOLUMN" ] ; then
    IOSTAT_2ndLINE_1stCOLUMN="$col"
  fi
done

# Jump into an infinite loop by calling iostat to print
# statistics every 60 seconds to stdout. Note that only
# devices with activity will be included.
# The first column of the output will be stored as $device
# and everything else as $usage.
$IOSTAT -d -I -x -z -t da -w 60 |
while read device usage
do

  # Skip empty lines.
  if [ -z "$device" ] ; then
    continue
  fi

  # First line of a new iostat run.
  if [ "$device" = "$IOSTAT_1stLINE_1stCOLUMN" ] ; then
    # Increment the inactivity counter of all devices.
    for dev in $DEVICES
    do
      eval old_counter=\$INACTIVITY_$dev
      new_counter=$(($old_counter+1))
      eval INACTIVITY_$dev=\$new_counter
    done
    continue
  fi

  # Second line of a new iostat run.
  if [ "$device" = "$IOSTAT_2ndLINE_1stCOLUMN" ] ; then
    # Check whether the inactivity counter of a device
    # has reached the configured threshold.
    for dev in $DEVICES
    do
      eval counter=\$INACTIVITY_$dev
      if [ $counter -eq $TIMEOUT ] ; then
        # Sending spindown command to $dev
        $CAMCONTROL stop $dev >/dev/null
      fi
    done
    continue
  fi

  # If $device is a device with activity
  # (which is true when the script comes to this position
  # because iostat is called to only print active devices)
  # then reset its inactivity counter.
  eval INACTIVITY_$device=0

done