> ------------------------------ > > Message: 4 > Date: Mon, 5 Apr 2010 11:55:21 -0500 > From: Matt Domsch <[email protected]> > Subject: Re: Power consumption -- real vs actual > To: John LLOYD <[email protected]> > Cc: "[email protected]" <[email protected]> > Message-ID: <[email protected]> > Content-Type: text/plain; charset=us-ascii > > On Mon, Apr 05, 2010 at 09:37:45AM -0700, John LLOYD wrote: > > FYI, commands were > > CPU heater: dd if=/dev/zero of=/dev/null & 8 to 16 times > > That's not a terribly good CPU-intensive load. Try something like > this a few times in parallel > > pi=$(echo "scale=100000; 4*a(1)" | bc -l) & > > I can feel the space under my desk heating up after just a few seconds > of this...
Heh. Also, a good cpu heater is compiling a kernel with a -j option of about (NCPUS * 1.5), so -j6 for a single quad core. Power is a relatively simple calculation. The PSU is rated for more than the maximum, just in case. That PSU rating is the max that PSU is capable of putting out, not what it draws at idle or anything like that. 110V * 7A = 770watts, which is the maximum your power cord (?) or other power infrastructure leading to the server can handle, which is less than the max the PSU can handle. So far, so good. The power draw measurements reported by the management tools, I assume is the reading from the power sensor on the motherboard. This will be quite a bit less than the actual power draw of the server at the wall socket, because it doesn't account for power usage by disk drives or other devices connected directly to the PSU. Unless that sensor is actually in the PSU. Regardless, it also won't account for the power loss of the PSU itself, so the only way to accurately know what is the power draw your infrastructure is experiencing, is to use a power (watt) meter at the "wall socket" or use an amp meter and voltage meter, also at the "wall socket." Hope that helps ~:^) Cheers, a _______________________________________________ Linux-PowerEdge mailing list [email protected] https://lists.us.dell.com/mailman/listinfo/linux-poweredge Please read the FAQ at http://lists.us.dell.com/faq
