[Beowulf] Green Cluster?

stephen mulcahy smulcahy at aplpi.com
Mon Jul 21 03:13:02 PDT 2008

Perry E. Metzger wrote:
> Here is how you can turn them on:
> http://en.wikipedia.org/wiki/Wake_on_lan
> There is even open source software described on that page.

Wake-on-Lan works very well - when it works. We were using it quite 
successfully on a small cluster we built for remote power on (after 
remote power off). We had to upgrade the BIOS recently for an AMD 
erratum and the BIOS upgrade had the unfortunate side-effect of mangling 
WOL while fixing the processor problem.

We can reset the WOL flags and re-enable it on individual nodes, but 
unfortunately when the nodes are power-cycled, the WOL flag goes back to 
its default (off) state. Given the typical use case of WOL, it seems 
unfortunate that a power cycle resets it.

We've made a stab at raising the matter with the vendor but since the 
cluster in question is only 20 nodes I don't think they take us 
seriously (or at least not as seriously as you folks with hundreds of 
nodes). So YMMV.


Stephen Mulcahy, Applepie Solutions Ltd., Innovation in Business Center,
GMIT, Dublin Rd, Galway, Ireland.  +353.91.751262  http://www.aplpi.com
Registered in Ireland, no. 289353 (5 Woodlands Avenue, Renmore, Galway)

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