Disk Power Management

From openSUSE

Introduction

Because bad things can happen [1][2][3] when your power-management disk parks or spins down too often, you may want to use the following scripts to manage the situation a little better.

The following HOWTO will take you through this step-by-step.

All of these steps will need have the appropriate sudo or su access.

Disk Power Management Configuration

Create a configuration file to management disk power management:

/etc/pm/config.d/disk

# Configure disk power management settings to ensure both
# long disk life and good power management.
#
# Space delimited list of disk devices this affects.
#
DEVICES_DISK_PM_NAMES="/dev/sda"
#
#
# Power management modes
#
# Powersave mode off
#  Disable APM and spin-down
#
DEVICES_DISK_PM_POWERSAVE_OFF="hdparm -q -B 255 -q -S 0"
#
# Powersave mode on
# Enable APM to conservative 200 and set spin-down for 21 minutes
#
DEVICES_DISK_PM_POWERSAVE_ON="hdparm -q -B 200 -q -S 252"

Note: Your laptop drive can get hot with no power management if you leave your laptop plugged in all the time. You may want to set DEVICES_DISK_PM_POWERSAVE_OFF to a large value, but not disabled completely. If you were going to do this, you might use something like: hdparm -q -B 254 -q -S 242

This means set the least power management, but not off, and spin down the disk after an hour.

Disk Power Management Script

Then create the power management script:

/etc/pm/power.d/disk

#!/bin/bash
. /usr/lib/pm-utils/functions
. /etc/pm/config.d/disk

if test -z "${DEVICES_DISK_PM_NAMES}"; then
        exit 1
fi

case "$1" in
        true)
                echo "**enabled pm for harddisk"
                for DISK_NAME in `echo ${DEVICES_DISK_PM_NAMES}`; do
                        ${DEVICES_DISK_PM_POWERSAVE_ON} ${DISK_NAME}
                done ;;
        false)
                echo "**disabled pm for harddisk"
                for DISK_NAME in `echo ${DEVICES_DISK_PM_NAMES}`; do
                        ${DEVICES_DISK_PM_POWERSAVE_OFF} ${DISK_NAME}
                done ;;
esac

Make the script executable.

chmod +x /etc/pm/power.d/disk

Test the script

You can then test the set up by using the following commands:

pm-powersave true
hdparm -I /dev/sda | grep 'Advanced Power'

An asterisk next to 'Advanced Power Management feature set' means its enabled. Now try this:

pm-powersave false
hdparm -I /dev/sda | grep 'Advanced Power'

No asterisk means it's disabled.

These settings are immediately accessible to kpowersave or gnome-power-manager and are used by default when plugging in your power adapter or removing it on a laptop.