1. Green cloud computing 1
Cs 595
Lecture 14

2. Number one concern of large
scale data centers?
Efficiency
affects:
accessibility
reliability
sustainability
costs
Can we affect datacenter efficiency with software?
yes!

3. Outline Power consumption in large datacenters
Alternative energy sources
Green hardware design best practices
Server level hardware
DC/DC, AC/DC conversions
Rack power distribution
UPS
Cooling
Building power distribution
Green software design best practices
Resource virtualization
Storage
Computational

4. Power Consumption in large datacenters
United States:
91 TWh (2013)
How much energy is is that?
Enough electricity to power every house/apartment in New York City for two years.
139 TWh (projected for 2020)
This amount of energy consumption doesn’t come from just the servers in the datacenters.

5. Power Consumption in large datacenters
Power Usage Effectiveness:
Industry metric for measuring the energy efficiency of a datacenter
Generally a ratio:
Total energy consumed by the datacenter
Total energy consumed by the IT equipment in the datacenter
PUE =

6. Power Consumption in large datacenters
PUE?
For every (PUE)Watt consumed at the datacenter, 1 Watt is delivered to the IT load
PUE = 𝑬𝑺𝑰𝑺+𝑬𝑰𝑻𝑺+𝑬𝑻𝑿+𝑬𝑯𝑽+𝑬𝑳𝑽+𝑬𝑭 𝑬𝑰𝑻𝑺 −𝑬𝑪𝑹𝑨𝑪 −𝑬𝑼𝑷𝑺 −𝑬𝑳𝑽+𝑬𝑵𝒆𝒕𝟏

7. Power Consumption in large datacenters
Distribution of total energy consumed by the datacenter:
ESIS – Consumption for supporting infrastructure
Lighting, office space, some network equipment, and cooling plant
EITS – Consumption for IT power substations
Servers, network, storage, and computer room air conditioners (CRACs)
ETX – Building Transformer losses
Step up/down conversions where energy is lost as heat
EHV – High voltage cable losses
Due to conductor resistance, loss generated as heat
ELV – Low voltage cable losses
EF – Consumption from fuel (natural gas, oil)

8. Power Consumption in large datacenters
Distribution of energy consumed by the datacenter IT equipment:
ECRAC – CRAC consumption
Computer Room Air Conditioning energy consumption
EUPS – Loss at UPS
Energy loss at uninterruptible power supplies
Enet1 – Network room energy consumption

9. 2014 Global Datacenter average PUE: 1.7
Large Cloud Vendor Datacenter Average PUE:
Amazon: 1.45
Microsoft: 1.13
Google: 1.12
Yahoo: 1.07
Facebook: 1.07

10. Power Consumption in large datacenters
Datacenter energy breakdown:
Computing: 52%
CPU – 15%
Server Power supply – 14%
Other Server Components – 15%
Storage – 4%
Networking – 4%
Support Systems: 48%
Cooling – 38%
UPS – 5%
Building Power Distribution/Transformer – 3%
PDU – 1%
Lighting – 1%

11. Power Consumption in large datacenters
Average and maximum power densities:
10 years ago:
100W – 175W per sq ft.
Modern data center:
Average: 225W
Maximum: 400W
Previous slide: 5,000 sq ft. datacenter
2mW of energy to dissipate!
Is this a large datacenter?
2011: Clemson University completes its new datacenter:
50,000sq ft.
25,000sq ft. -office space
25,000sq ft. - rack space
4.5mW at full capacity (current)

12. alternative energy sources - solar
Solar Constant: amount of incoming solar electromagnetic radiation
~1.36 kW/m2 (maximum)
Average solar panel efficiency: 14%
19w/ft2 (best condition)
Closer to 10w/ft2
5,000 sq ft. datacenter:
2mW  200,000 sq ft of solar panels! (4.59 acres)
Semprius (solar startup): 33.9%
1.89 acres 
Energy storage?
Datacenter placement?
Cloudy?

13. alternative energy sources - Wind
Advantages:
Generate 250W – 1.8MW per turbine
Green, renewable energy
Disadvantages:
Unpredictable
Noise
Aesthetics

14. alternative energy sources Geothermal
Cooling, Cooling, Cooling!
Approach 1:
Climate cooling
Strategic placement of datacenter that allows outside air temperature to help regulate inside temperature.
Approach 2:
Ground cooling
Average temperature at 20ft below earth’s surface: 54F
Datacenters can use closed loop venting ducts underground to dissipate the heat produced by equipment.

15. Green hardware design best practices Server level hardware - CPU
CPUs with lower Thermal Design Power (TDP):
Intel Kaby Lake Xeon:
14nm manufacturing process
E3-1280v6 – 4 core w/HT (8 threads)
Max TDP: 74W
AMD Opteron:
32nm manufacturing process
6366 HE – 16 core
Max TDP: 85W
6386 SE – 16 core
Max TDP: 140W
Goal: Increase Flops/Watt

16. Green hardware design best practices Server level hardware - CPU
Performance per watt: rate of computation that can be delivered by a CPU for every Watt of power consumed.
#1: 6.67 GFlops/W
#1 - #10 average: 4.82 GFlops/W
#400: MFlops/W
Is this green?

17. Green hardware design best practices Server level hardware - Storage
HDD vs SSD:
WD Caviar Blue 500 GB SATA 6GB/s
Read/Write: 6.8W
Idle: 6.1W
Read/Write performance: 130MB/s
Seagate Cheetah 15k 146GB SAS
Read/Write: 17.2W
Idle: 14.4W
Read/Write performance: 186MB/s
HDD vs SSD:
OCZ Vertex 3 240GB SATA 6GB/s
Read/Write: 1.25W
Idle: 0.53W
Read/Write performance: >500MB/s
Cost per GB?
HDD: ~$0.03/GB
SSD: ~$0.40/GB

18. Green hardware design best practices Server level hardware - RAm
DDR2 vs DDR3
DDR2 – 1.8v
1066 MT/s
80nm manufacturing process
DDR3 – 1.25v – 1.65v
2133 MT/s
20nm (Samsung, 2012)
Current Standard: DDR4:
1v – 1.2v
Up to 4266 MT/s (megatransfers/sec)
20nm current manufacturing process

19. Green hardware design best practices Server level hardware - motherboard
85% of power consumed by motherboard:
Voltage Regulators
Converts voltage provided by power supply into appropriate voltages needed by the CPU, RAM, Chipsets, etc.
Also used to “clean up” DC voltage from the power supply.
Linear voltage regulator:
Solid state semiconductor to regulate voltages
~60% efficient
Switching voltage regulator:
Circuit that transitions between full regulated out, low-current output, and off
Generates less heat  ~95% efficient
Use motherboard with switching voltage regulators for higher efficiency.

20. Green hardware design best practices Server level hardware - network
Use of power efficient networking components:
Switches
Routers
NICs
Devices can be scaled depending on demand
Device low power mode
Turn off ports
Goal:
Increase Bandwidth/Watt in communication components

21. Green hardware design best practices Ac/Dc, Dc/Dc conversions
AC/DC conversions:
Translates non-polarized alternating current (building power feed) to polarized direct current (used by IT components)
Not 100% efficient
Heat generated equates to loss
Also must be dissipated requiring more power consumption!
AC/DC conversion locations:
Building feed to UPS
Server Power supply
EPA Energy Star rating – 80% efficiency across all rated power output.
Switching voltage regulator (previous slides)

22. Green hardware design best practices Rack power distribution
Problem with current rack deployment?
Rack mount servers connected to UPS
Power transforms at UPS and again at the server
Solution (Google):
Remove unneeded AC/DC, DC/AC transformations
AC from building line feed connects to UPS in the rack
UPS performs AC/DC transformation
Servers connect directly to UPS’s DC output

23. Green hardware design best practices UPS
Uninterruptible Power Supply:
Stores power to ensure IT component operations in the case of short power outages
Also used to “clean” electricity from outside source
Efficiency: 92% - 95%
Arranged in a 2N configuration for fault tolerance.
Example: 20,000sq ft. datacenter at 120w/sq ft.
Electricity cost: $0.10/kWh
95% efficient vs 92% efficient UPS
$72,000 annual difference in electricity costs
Generated $72,000 worth of heat!!

24. Green Computing Current system extremely wasteful
Need energy to run equipment
Need energy to cool
1000 racks, 25,000 sq ft, 10MW for computing, 5MW to dissipate heat
Need a system more efficient, less expensive strategy with immediate impact on energy consumption

25. Data Centers
Focus by green computing movement on data centers (SUVs of the tech world)
6,000 data centers in US
Cost: $4.5B (more than used by all color TVs in US)
In 2007, DOE reported data centers 1.5% of all electricity in US
Greenhouse gas emission projected to more than double from 2007 to 2020

26. Data Centers
Within a few years, cost of power for data center can exceed cost of original capital investment

27. Goal
Fed. Gov. want datacenter energy consumption to be reduced by at least 10%
Same as energy consumed by 1M average US households

30. Data Center Metrics Metrics Green Grid – group of IT professionals
SPECPowerjbb benchmark and DCiE from Green Grid
Green Grid – group of IT professionals
Power Usage Effectiveness PUE
PUE = Total facility power/IT equipment power
Data Center infrastructure Efficiency metric DCiE
1/PUE

31. Future Vision Sources of computing power in remote server warehouses
Located near renewable energy sources – wind, solar
Usage shifts across globe depending on where energy most abundant

32. Current approaches Some “low hanging fruit” approaches
Orient racks of servers to exhaust in a uniform direction
Hot/cold isles
Higher fruit - Microsoft
Built near hydroelectric power in WA
Built in Ireland - can air cool, 50% more energy efficient
Countries with favorable climates: Canada, Finland, Sweden and Switzerland

33. Current approaches
Google – trying to reduce carbon footprint Carbon footprint includes direct fuel use, purchased electricity and business travel, employee commuting, construction, server manufacturing
According to Google, its data centers use ½ industry’s average amount of power
How? Ultra efficient evaporative cooling (customized)
Yahoo (are they back??)
Data centers also carbon-neutral

34. Current approaches US government Green Grid consortium Green500
EPA has phase-one of Energy Star standards for servers
Measure server power supply efficiency and energy consumption while idle
Must also measure energy use at peak demand
Green Grid consortium
Dell, IBM, Sun, Cisco, Lockheed Martin, Microsoft, AMD, Intel, …
Green500
500 most green supercomputers

35. Data Center Product Specification Completion
2009
Servers v1.0
2011
Data Center Buildings Program
2012
UPS v1.0 (uninterruptable power supply)
2013
Servers 2.0
Storage v1.0
2014
Large Network Equipment v1.0
2015
Data Center Cooling Equipment v1.0

36. Current approaches
Replace old computers with new more energy-efficient
But manufacturing through day-to-day uses energy
Dell - reducing hazardous substances in computers, OptiPlex 50% more energy efficient
Greenest computer company – VirtualBoxImages
What is “Greenest computer ever” ?
Is MacBook air (pro) greenest?

37. Goals for Future Green Cloud computing
Consider energy to manufacture, operate, dispose of wastes
Sense and optimize world around us
Predict and respond to future events by modeling behavior (grown in performance)
Benefit of digital alternative to physical activities
E-newspapers, online shopping
Personal energy meter??