Power-managment of slave nodes

Felix Rauch rauch at inf.ethz.ch
Wed Mar 7 01:18:49 PST 2001

[adjusted quoting]

On Tue, 6 Mar 2001, Kyle Sheumaker wrote:
> On March 6, Brian Marsden <marsden at scripps.edu> wrote:
> > 2) Wake-on-LAN - I'm not 100% clear on whether this listens for a specific
> >    packet or whether it will just fire the machine up if a packet comes
> >    along with the NICs MAC address. If the later is the case I think we
> >    are snookered since we use PBS as the queueing system which I believe
> >    sends out packets to query nodes every now and then.

AFAIR Wake-on-LAN waits for a broadcast packet with a magic-pattern
and the destination machines MAC address in the middle. Normal packets
do not wake the machine.

> I have played with wake-on-lan and not had a lot of luck.  It is a
> special packet (http://www.scyld.com/expert/wake-on-lan.html), but
> some motherboards / nics just don't seem to want to "wake."

When we played with our Cluster of Dell-machines, we found ot that we
have to power off the machines at the right time. If we pressed
CTRL-ALT-DEL to reboot the machine and powered them off when de BIOS
screen appeared, Wake-on-Lan most likely didn't work, as the machines
were completely off. It seemed to work however, if we did a "shutdown -h" 
and switched the machines off when they reached runlevel 0. So a
combination of APM and "halt -p" would probably do the trick without
having to press the power-button.

- Felix
Felix Rauch                      | Email: rauch at inf.ethz.ch
Institute for Computer Systems   | Homepage: http://www.cs.inf.ethz.ch/~rauch/
ETH Zentrum / RZ H18             | Phone: ++41 1 632 7489
CH - 8092 Zuerich / Switzerland  | Fax:   ++41 1 632 1307

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