Kill the power faster than poweroff?

Ariel Sabiguero asabigue at fing.edu.uy
Thu Sep 11 06:19:38 EDT 2003


How about

     halt -p -f

or

     poweroff -f
....
I tried it and it takes 3s instead of 20 or more :-)

 From the man page:

NOTES
       Under  older sysvinit releases , reboot and halt should never be 
called directly. From release 2.74 on halt and reboot
       invoke shutdown(8) if the system is not in runlevel 0 or 6. This 
means that if halt or reboot cannot find out the cur­
       rent runlevel (for example, when /var/run/utmp hasn't been 
initialized correctly) shutdown will be called, which might
       not be what you want.  Use the -f flag if you want to do a hard 
halt or reboot.

It seems that it performs the sync call BEFORE killing the system but I 
think you should be careful.

Regards

Ariel

David Mathog wrote:

>Is there a faster way to shutdown a system and kill
>the power than "poweroff"?  This is for use in
>emergency overheating conditions, where something
>that's effectively the equivalent of:
>
>  % sync
>  [turn off the power supply]
>
>is desired.
>
>lm_sensors and mondo are running on our Athlon 2200MP
>cluster and I'm concerned that in the event of a
>catastrophic failure of the cooling system the CPUs
>might overheat before the poweroff sequence completes.
>Not necessarily flame out immediately, but at least
>get hot enough so that they no longer run correctly,
>then poweroff wouldn't be able to complete, and then
>it's roasted CPU time.
>
>Tyan 2466 motherboards.
>
>This is only for emergency overheating, poweroff is
>fine for a normal shutdown.
>
>Thanks,
>
>David Mathog
>mathog at caltech.edu
>Manager, Sequence Analysis Facility, Biology Division, Caltech
>_______________________________________________
>Beowulf mailing list, Beowulf at beowulf.org
>To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
>
>  
>


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