How to switch off your usb external drive after umount and stop its spinning heads?

How to switch off your usb external drive after umount and stop its spinning heads?

The following article gives some hints, which I summarize here.

http://www.lesswatts.org/projects/devices-power-management/usb.php

1) find the device to switch off (eg. the USB Mouse)

root@rpolli:/sys/bus/usb/devices# lsusb

Bus 004 Device 005: ID 046d:c050 Logitech, Inc. RX 250 Optical Mouse

Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

2) Go to directory

# cd /sys/bus/usb/devices/4-2

3) check that the device is the one we need

# cat product

USB-PS/2 Optical Mouse

4) disable it

# echo suspend > power/level

HTH