[CentOS] Wake on LAN

Sun Apr 5 03:31:39 UTC 2009
Gordon McLellan <gordonthree at gmail.com>

On Sat, Apr 4, 2009 at 4:31 PM, Timothy Murphy <gayleard at eircom.net> wrote:
> Has anyone experience with WOL under Centos (5.3).?
> If so, how exactly do you put the machine to sleep,
> and how exactly do you wake it up remotely?

Put the machine in a suspend to ram state using acpi:

echo -n mem > /sys/power/state
you can use disk instead of mem

Machine should go down real quick - if you've got services / devices
running that aren't compatible with suspend, it may wake up right

This "works for me" under Fedora 10, no idea about how it would work
under Centos 5.3 - but it appears the interface is there regardless.
I had to unmount nfs directories and unload my network driver before
the system would stay asleep.  if you put the sleep command in a
script, when the OS wakes, it will continue executing the script,
making it easy to resume services / devices that needed to be
discontinued prior to sleeping.