Wednesday Aug 22, 2007
You will be mislead if you look at graphs of watts that do not show
"zero watts" to "maximum watts". The graph below
makes it appear that you start at max watts and go down all the
way as your utilisation decreases.
Below is a graph that is more like what modern servers can do with
the latest power saving features.
Poor graphs to make changes look bigger than they are.
Finding where to save money actually requires a different graph. One
needs to look at "watts per unit of work" which equates to
"watts per performance". Looking at the graph below it now becomes
quit quite clear how to save watts, you need to have your server at over
50% utilization even if you have the latest power-saving technology.
This was discussed yesterday in this blog.
You can see in this graph that five servers running at 10% utilisation uses 1200 watts/unit-of-work versus one server running at 50%
utilisation only uses 400 watts/unit-of-work. The 10% case requires
3 times more power to do the same amount of work!
Get eco smart, drive up your utilisation through good policy, or the
correct use of consolidation and/or virtualisation.
Tuesday Aug 21, 2007
Truly being Eco is about looking at the right things and highlighting
them in a way so you can make real judgments that really make a difference.
A fellow Sun employee gave me a great analogy, if you want to save
power switch off the light! Obvious. But too often we try to
use fancy technology to save energy when proper policy is more important.
If you leave incandescent lights on all day, switching to CFL
(compact florescent lights = better technology) can save energy.
but if you "switch it off during the daylight hours" (better policy) you
can save a lot more.
How does this apply to datacenters? Everyone needs to change
their policies to operate servers at not an insane 20-30% utilisation
but to 50% or more.
There are all kinds of virtualisation technologies that can be used
if for some reason you can't simply drive up the load. Take two
servers at 25% and consolidate them on to one server running at 50%
utilization and "turn the other one off".
There are lots of virtualisation technologies VMware, Xen, Solaris 10 Zones,... Another thing to consider is that Solaris 10 zones have no overhead for CPU, IO, and network. Overheads reduced performance but they also require one to burn more CPU watts. But use whatever technology suits your needs.
...more on using fancy datacenter power saving technology tomorrow...
Monday Dec 18, 2006
As the BM Seer talked about in http://blogs.sun.com/bmseer/entry/wattage_charts_to_think_about
huge saving can be made by increasing utilization on servers. These
gains can be seen in real data centers.
For example take a look at the blog posting by an
Infrastructure Coordinator for a large Dutch IT Services provider
http://virtualize.wordpress.com/2006/12/18/power-savings-through-virtualization/.
This was also mentioned in Sun's Peter Jenkin's blog.
By the way the Solaris virtualization
features can create the same savings. Since the various Solaris virtualization
features are designed to be extremely efficient (as we've shown in the past
for example: http://blogs.sun.com/bmseer/entry/virtually_no_overhead_solaris_zones) you may even save more with the near zero% overhead of Solaris.
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"quit clear how to save watts" ... I thi...
thanks fixed.