[PLUG] SATA II, mdadm and soft power off

Galen Seitz galens at seitzassoc.com
Sat May 12 16:10:30 UTC 2007


John Jason Jordan wrote:

> *Something* is sending a kill signal to the power supply, i.e., the
> soft power off is being triggered. I am assuming it is the same signal
> that the OS sends at the end after the user has clicked on the Shutdown
> icon. The mystery is what could be doing it. I wish I knew how the soft
> power off works.
> 
> Any ideas and suggestions welcome, regardless of what wild hair spawned
> them.

Since you are confident the system is not overheating, and your power 
supply is more than adequate, that seems to leave two possibilities. 
Either a software shutdown is occurring, or electrical noise is 
coupling into the power control circuit.  Here are some things you 
could try to help determine the problem.

Rather than trying to build an md array, try running iozone or bonnie 
on both disks simultaneously.  If you can make it fail this way, then 
the problem is not md.

Connect the power supply enable signal to ground.  This will force the 
supply on, regardless of the front panel switch or motherboard.  If 
you can build the md array and run without crashes with power supply 
forced on, this would suggest that electrical noise is causing the 
power supply shutdown.  The power supply enable signal is on the power 
supply connector.  If you want to try this, send an email and I'll 
give you instructions.


Personally, I think I would start shopping for a different motherboard.

galen



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