BM Seer Unofficial thoughts from an anonymous Sun employee

Eco Actual fancy power saving features on

Wednesday Aug 22, 2007

I could hear the cries in the blogosphere as I posted the entry earlier today... "these graphs are based on what?"

...actually there were based on a real system, but I can't share the data. I searched and found the following public data(only 8 months old):
http://www.anandtech.com/printarticle.aspx?i=2892

they have graphs that show:

  • workload1: two 2.6GHz Opt 2218 8GB DDR2 that go from 260watts(100% util) down to 165 watts (20% util)
  • workload2: two 2.6GHz Opt 2218 8GB DDR2 that go from 275watts(100% util) down to 190 watts (20% util)
  • workload1: two 3GHz Xeon 5150 8GB FB-DIMMS that go from 325watts(100% util) down to 250 watts (20% util)
  • workload2: two 3GHz Xeon 5150 8GB FB-DIMMS that go from 325watts(100% util) down to 270 watts (20% util)
...Not hard to imagine going from 400watts with the latest power savings to 200 watts at 0% util, is it?

They did make a mistake by graphing perf/watt instead of watt/perf. looking at their graphs we can make a table of the watt/perf:

watt/performance workload1="DVD Store", 8GB servers
%Util3 GHz Xeon
2chip woodcrest		2.6GHz Opteron
2chip 2218
20%37 watt/perf33 watt/perf
40%22 watt/perf18 watt/perf
60%14 watt/perf13 watt/perf
80%11 watt/perf11 watt/perf
100% 9 watt/perf11 watt/perf

Not a huge difference between systems, but a huge difference between the same system running at 20% util vs. 60% util for example. In either case it is 2.6x more wasteful running at 20% util vs. 60% util. That means you use 2.6x more watts!!!

This data is actually worse than what I showed.

Get eco smart! Sure, turn on the power saving features. But if you really want save $ and be a hero you must put effort into driving up utilisation.

I've been talking about single servers, but this is not about going one by one through all of your servers, any datacenter has RACKS and RACKS of servers, which should make it easier to drive up the utilisation en masse.

[2] Comments
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Posted at 10:17AM Aug 22, 2007 in Wattage-Power
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Recently AnadTech posted on some lower voltage servers at:
http://www.anandtech.com/IT/showdoc.aspx?i=3039

The still plot perf/watt and not watt/perf (you got to correct this guys!)

But they do get to a lot of the right conclusions:

"However, we think that more organizations should be thinking about power in terms of utilization."

"... why not try server consolidation? As you have seen the majority of system power is used just to run the fans, chipset, CPU, etc. when the server is at idle. If you could take two systems that consume 300 watts of power and combine them into one server, isn't that worth more to your organization? Take a look at VMWare, XenSource, and other virtualization solutions, if you really want to lower operating costs relating to power consumption."

They only seem to test at 8GB, and they really need to dig into larger memory configurations and measure power on those other variations.

Posted by BM Seer on August 22, 2007 at 01:37 PM PDT #

another posting on watt comparisons, memory is highlighted
http://arstechnica.com/news.ars/post/20070724-amd-vs-intel-power-efficiency-in-the-server-room.html

but still not seeing large-memory Xeon/Opteron at 16GB, 32GB, & 64GB like we posted here a while back:
http://blogs.sun.com/bmseer/entry/another_datapoint_of_woodcrest_burning

Posted by BM Seer on August 22, 2007 at 02:55 PM PDT #

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