A.10. Advanced Power Management
APM allows control of the power from
software. This can be a blessing and a curse.
The blessing is that the machine can be cleanly and totally
shut down remotely. You may want to do this if the remote site is
maintaining their power supply.
The curse is that once powered down the machine will not
start up again until the Power button is
physically pressed. Some machines have a BIOS or
motherboard setting to defeat this unhelpful behaviour.
| Errors when typing shutdown are worse
with APM |
---|
| Be careful not to confuse shutdown -r
now, which cleanly reboots the machine, with
shutdown -h now, which cleanly powers down the
machine. Someone will need to physically press the
Power button if you choose wrongly. |
If you are serious about remote site computing then you
should investigate remote power switches from companies like Western Telematic, Server Technology and many
others. Some models include built-in terminal servers, built-in
modems and RS-232 lines to simulate a
UPS input power failure (and thus shut the
Linux system down cleanly
before removing power).