Help on cluster hang problem...

d.bussenschutt at d.bussenschutt at
Mon Jun 4 17:02:54 PDT 2001

If you have the "power button doesn't work" problem, try holding the 
button down for either 6 or 10 seconds (depending on the bios), and you'll 
find it will power off then.  It comes about because the bios has APM 
(advanced power management) enabled, and the linux kernel you are using 
has APM support compiled in, and is "hooking" into the BIOS's features for 
"soft-power-down".    The idea behind this is that when you press the 
power button the hook does a "init 0", and allows the OS to shut itself 
down first, before powering down the CPU etc.  either disable APM in the 
bios, or in the kernel (or better still both). I mean when working with 
high-performance clusters you don't want the nodes to "go to 
sleep"...reduce clock speed of cpu, spin down it's HDD's, turn off its 
(probably nonexistant) display device, etc etc. You want MAXIMUM response 
from nodes, irrespective of how much juice they suck from the power piont. 


Greg Lindahl wrote:

> On Tue, May 29, 2001 at 10:26:39PM -0400, David Vos wrote:
> > Hmmm.  I've seen Windows do that to enough computers I doubt the 
> > is the power supply.  Although to make Linux hang like that is usually 
> > hardware problem.
> If it weren't for the "power button doesn't work", which I haven't
> seen before, I'd certainly agree that it's likely a random hardware
> problem. You've seen Windows hang machines to the point where the
> power button doesn't do anything? I never have. But then again I don't
> use Windows much.
> -- g
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Well I've seen once or twice on my Linux  desktop, it starts out with the 
keyboard and mouse not working.
Then when I press the power botton, the keyboard resets (led's flash) and 
then nothing...

But I doubt it is a hardware problem 'cause then it should have happend 
more often (?)


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