[Linux-cluster] 2-node tie-breaking

[Lon Hohberger]

On Fri, 2008-02-08 at 15:32 +0000, gordan at bobich.net wrote:

> I just had another thought. Most motherboards these days are ATX, which 
> means ATX type "short-pins-to-power-on" power switches. That means that as 
> a _REALLY_ cheap solution I could just get something like a small relay 
> switch and wire it into the serial port. When a pin on RS232 goes high 
> (e.g. DTR), it activates the switch. I think it would be pretty reliable, 
> and the total cost of components would be pennies. The fence agent would 
> also be a total of about 10 lines of code, too. :)

It'd have to be a 'press-and-hold' sort of thing.  E.g. either activate
or deactivate DTR for 5+ seconds. ;)

"Reboot" -

Power-off:
+dtr
sleep 5
-dtr

Power-on:
+dtr
-dtr

This reminds me of the 'clapper' agent someone suggested awhile ago.

-- Lon