Power-managment of slave nodes

[Brian Marsden]

Dear all,

 I look after a 96 processor, 48 node, Pentium III linux cluster. The
owners have just received their first electricity bill for the machine and
unsuprisingly have had a nasty shock! They are now desperate to find ways
to keep the bill as low as possible.

 One solution put forward has been to have nodes shut themselves down
using APM when not in use. Then when a node is needed for a job, it could
be switched back on via wake-on-LAN on the ethernet card. I see a number of
problems associated with this:

1) APM is not supported under Linux 2.2 for SMP. However I believe that it
   is for 2.4 - can anyone comment on this?
2) Wake-on-LAN - I'm not 100% clear on whether this listens for a specific
   packet or whether it will just fire the machine up if a packet comes
   along with the NICs MAC address. If the later is the case I think we
   are snookered since we use PBS as the queueing system which I believe
   sends out packets to query nodes every now and then.

 Before I spend more time delving deeper into these problems, has anyone
ever attempted to try to do all of this? If so, what are the perils and
pitfalls? Is this a completely crazy idea?

Thanks

Brian.

-- 
---------------------------------------------------------------------
 Brian Marsden        			  Email: marsden at scripps.edu
 TSRI, San Diego, USA.  Phone: +1 858 784 8698  Fax: +1 858 784 8299
---------------------------------------------------------------------