DATA CENTER POWER CONSUMPTION
In 2005 data center power usage was 1% of the worlds
The current power usage is estimated to be as high as 1.5%
world wide and up to 2.2% of US power consumption.
Why should you care?
Every year there are rolling blackouts though the summer
because utilities cannot keep up with demand.
Energy costs are higher than equipment costs.
Power Usage Effectiveness (PUE) developed by the Green Grid
is a widely accepted measure of data center efficiency.
Total data center energy consumption/IT energy
A PUE of one means that all energy consumptions is being used
by the servers, storage devices and networking equipment.
Reaching one is the goal, but may not be possible currently…
However, Google has reached reach a Power Usage
Effectiveness (PUE) of 1.16.
THERE IS A BETTER WAY…
According to Google “if all data centers
operated at the same efficiency as ours,
the U.S. alone would save enough
electricity to power every household within
the city limits of Atlanta, Los Angeles,
Chicago, and Washington, D.C.”
CASE STUDY: GOOGLE
How did they do it?
The average power supply converts power from AC to DC accounting for 30
to 40% in power loss.
This process also produces heat
Google power supplies do not perform this costly conversion and
have an integrated UPS.
“We’ve also cut out 2 of the AC / DC conversion stages by putting back-up
batteries on the server racks themselves.”
GOOGLE CASE STUDY
Google tracks its PUE
Data centers are run at 80 degree Fahrenheit or more
This “conforms with both the American Society of Heating, Refrigerating, and
Air Conditioning Engineers' recommendations and most IT equipment
Data centers can be cooled without chillers
Remaining chillers have disabled “dehumidifying and reheating functions on
CRACs. Most are set to dehumidify air to 40% and reheat air if the return air
is too cold, but these functions aren’t needed.”
Each data center element is designed to operate at optimal
GOOGLE CASE STUDY
“Customizing servers for efficient power use
We also omit parts on servers that aren't needed for our
applications. Hardware is limited to what is necessary for the
applications to run, and does not include unnecessary
components such as peripheral connectors or video cards. We
also optimize our servers and racks to use minimal fan power,
and the fans are controlled to spin only as fast as necessary to
keep the server temperature below a threshold.“
FACEBOOK CASE STUDY
“Facebook recently disclosed its plans to adopt
a novel power distribution design pioneered by
Google that removes uninterruptible power
supply (UPS) and power distribution units
(PDUs) from the data center. The new design
shifts the UPS and battery backup functions
from the data center into the cabinet by adding
a 12 volt battery to each server power supply.”
Video Tour of Facebooks 1.07 PUE datacenter
ROLE OF SOFTWARE
”(T)he only way to have software consume zero resources is not
to run it at all. Even running very well-behaved software at the
minimum will, in practice, require some resource overhead.”
Lean Operating systems
Virtualization is useful for consolidation of under utilized software
DO: consolidate servers that typically have usage under 70%
DO NOT: consolidate servers that have usage higher than 90%
Unless the server resources are more than enough to cover usage patterns
including the other virtualized servers consolidated into the new server
WARNING: Consolidating server high usage servers on one server may be a
recipe for disaster.
Remember: Virtualization can lead to the need to rework cooling
in the data center.
Fewer machines could lead to unnecessary cooling of space no longer
occupied by servers. This could result in wasted cooling.
LEAN OPERATING SYSTEMS
Windows server 2008 R2 Core
Uses less disk space
Standard 7.5 GB
Core 3.5 GB
What’s the big deal space is cheap?
Hard drive usage must be powered
Additional load for backups
Can be a huge deal in a virtualized environment
Memory usage is also decreased by 34%
Multiply that by 100 in a virtual environment, the resource savings is huge
Write event-triggered not time-based checks
Use batch processing for processes that cannot be event
Make sure batch jobs can be adjusted for time conflicts
Avoid memory leaks
Release memory when it is no longer needed, don’t wait for
the system to do it foru you.
Buffer/batch I/O requests
EFFICIENT SYSTEM STACK
“Features to reduce power consumption of underutilized
system resources have become pervasive in even the largest
systems, and the software layers responsible for managing
those resources must evolve in turn”
Increase performance of resources in use
Reduce power consumption for resources not in use
“Resource consumers clearly have a significant
opportunity either to contribute to or undermine the
efficiency of the broader stack. Though getting
programmers to think differently about the way they
design software is more than a technical problem,
tools such as PowerTOP represent a great first step by
providing programmers and administrators with
observability into software inefficiency, a point of
reference for optimization, and awareness of the
important role software plays in energy-efficient
What is better one really powerful server of several low
Answer: It depends.
Many low powered servers are ideal for transactional loads
Powerful servers are better for simulation and computation
Hard Disk DriveHDD vs Solid State Drives (SDD)
Uses 80% of maximum power draw at start-up
Linear proportion usage to power relationship
This means that any HDD active, but running at under
80% utilization is wasting energy.
So is the answer to use all solid state drives?
That is one possible answer, but it is currently an expensive answer.
Virtualization is one possible method of achieving this goal
Shared storage arrays are another
Increased use of technologies such as memcached for frequently accessed
This technique uses RAM caching
Used in conjunction with compression this can be very useful for
Hybrid SDD/HDD storage systems managed intelligently
"Any intelligent fool can make things bigger, more
complex, and more violent. It takes a touch of genius -and a lot of courage -- to move in the opposite
direction.” ~Albert Einstein
In IT this kind of thinking results in huge payoffs when