Andrew Kutz

Thesis◦ The energy efficiency of today’s information

technology (IT) infrastructure is not doubling every two years along with performance, leading to very high performing, very inefficient data centers. The inefficiencies in energy consumption must be mitigated so that efficiency will catch up with performance.

2

Agenda◦ Power in the data center today◦ Areas for improvement◦ Recommendations

3

Agenda◦ Power in the data center today

Data center power distribution Data center power consumption The result

◦ Areas for improvement◦ Recommendations

4

Data center power distribution

5

HVAC

Room, misc.

Power distribution units

RacksCompute Servers

CPUStorage

UPS

Storage devices

Power StationBackup Generator(s)

PSU

Data center power consumption

◦ The breakdown leaves room for plenty of areas of improvement.

6

IT equipment

Server components

40 %

60%

35%

30% 30%

20% 20%

15% 20%15% 15%

IT equipment

Power delivery

Cooling equipment

Compute servers

Storage servers

Comm. & misc.

CPUs

CPU VR loss

Memory

HDDs and misc.

PSU loss

Data center

Source: Dell, APC, SUN

The result

7

75x

16x

Source: Christian Belady

Agenda◦ Power in the data center today◦ Areas for improvement

Processors Power supplies Power delivery Cooling

◦ Recommendations

8

Processors – Last gen processors were power hungry beasts!◦ A first-generation AMD Opteron (856) at 3.0GHz

used 92.6W◦ According to AMD, processors can use between

50-60% of rated power when in an idle state.◦ That means the same processor was consuming

46.3- 55.56W of energy when doing nothing.

9

Processors – Multi-core CPUs◦ Multiple cores on a single chip and processor

development helps to reduce energy consumption An Intel Xeon 3.80 GHz used110W An Intel Xeon E5345 2.33 GHz

Quad-Core uses 80W. 2.45 times the processing power at

.72 times the energy consumption!

10

Processors – Power stepping CPUs◦ CPUs can step down into reduced performance

modes by adjusting frequency and voltage in synchronization with load.

11

Source: AMD

Power supplies – Today’s problems …◦ The typical efficiency of today’s power supply is

anywhere between 75-80%.◦ 1000 servers @ 400W @ 75% efficiency means

100kW is being radiated into heat that cooling systems must remove.

◦ 100kW equals 341,400 BTU.◦ At 0.10 USD/ kWh it costs 52,317.07 USDover a 4

year life cycle to remove the extra heat.

12

Power supplies – Are tomorrow’s opportunities◦ Power supplies being developed with digital

feedback control can maintain 90-95% efficiency over a wide range.

◦ 1000 servers @ 400 W @ 95% efficiency means only 20kW, or 68,280 BTU, is radiated as heat.

◦ At 0.10 USD / kWh it costs 14,953.32 USD over a four year life cycle to remove the extra heat.

◦ Increasing PSU efficiency by 20% reduces wasted cooling costs by four fifths.

13

Power delivery – Uninterruptible Power Supplies (UPS)◦ UPS devices are long-term investments. However, it

may be time to upgrade.

◦ May lose .59% efficiency for every year a UPS device is in service. That is a potential improvement of 10.03% for upgrading a UPS from 1990.

14

Source: Eaton Power

Cooling – Inefficiencies◦ General cooling is a guaranteed way to generate

hot spots, resulting in wasted energy. ◦ Over-cooling – Cooling systems are often

designed to run at maximum capacity at all times, resulting in wasted energy.

15

Cooling – Improving Efficiency◦ Targeted cooling and right-sizing

The closer the cooling is to the source of the heat, the better.

While it is tempting to buy big, only so much cooling is needed. Any more than is needed is wasted energy.

Take off the sweaters!◦ Remove the …

The heat – the biggest barrier to cooling is heat! The gaps – seal cable cut-outs and install blanking panels.

◦ Investigate liquid cooling Or how I learned to stop worrying and learned to love the

H2O. APC, IBM, Liebert are offering liquid cooled rack solutions.

16

Direct Current (DC) Power Delivery◦ Pros

Delivering DC power directly may offer greater energy efficiency by reducing the number of distinct ACDC inductors.

One side effect would be reducing the amount of cooling required per server since excess heat in the ACDC conversion is localized to fewer areas.

◦ Cons Only one major vendor (Rackable Systems) currently offers

full DC support in its x86 server product line. This could lead to vendor lock-in.

Although used for years by the TelCo industry, the number of engineers experienced in DC power vs. AC power is small.

17

Cooling – Improving efficiency (continued)◦ Variable Frequency Drives (VFDs)

A subset of adjustable speed drives (ASDs). Adjusts speed by altering the frequency and

voltage output. Cooling equipment with VFDs can

dynamically adjust the speed of the fan based on different input factors such as static pressure using a pitot tube and manometer.

Reducing the output voltage when extra cooling is not need leads to less energy consumption.

18

Agenda◦ Power in the data center today◦ Areas for improvement◦ Recommendations

Technical Business Community

19

Technical◦ Remember, CPUs represent almost 10% of a data

center’s power consumption.◦ Rethink power and cooling designs and systems.◦ Explore consolidation efforts:

Compute Virtualization Blades

Storage Shared storage – SANs, Filers Storage designs – massive array of idle disks (MAID),

data deduplication

20

Technical◦ Delivering DC power directly to the servers

sounds like a good idea, but it should be classified under “wait and see.”

21

Business◦ Make the power and cooling issue a bold line item

on the CxO’s budget.◦ Consider creative options:

Rent roof space to local utilities companies for solar panels and buy back cheap energy.

Move the data center to a colder climate.◦ Pressure vendors to think green. Purchasing

power is the greatest bargaining tool that customers have.

◦ Every percent counts. A 400kW data center @ 0.10 USD / kW = 245,173.46 USD / year. 1% will result in an annual savings of 3,504 USD. 15% = 36,775.77 USD. 30% = 73,551.54 USD.

22

Community◦ Join organizations, such as the green grid, that

are dedicated to helping to build an energy efficient data center.

◦ Pay attention to existing and emerging standards like Green Grid’s Power Usage Effectiveness (PUE) when buying new equipment to ensure energy efficiency.

◦ The Energy Star is expanding to cover servers.◦ Encourage vendors who are already thinking

green to keep it up: Fujitsu-Siemens, NEC, IBM, HP, Dell, and Sun to name a few.

23

◦ The opportunity to increase efficiency will probably not disappear while electricity prices are not prohibitively expensive and compute power is cheap.

◦ The government and industry initiatives are developing and will continue to fine tune energy efficiency related standards. Efficiency used to be Power Out / Power In. It will be transformed to Productivity Out / Power In.

◦ To have the most effect, attack the largest culprit first – processors. CPUs account for almost 10% of a data center’s energy consumption. Save the power leader, save the world!

24

◦ AMD – http://enterprise.amd.com/Downloads/34146D_PC_WP.pdf

◦ APC – http://www.apcmedia.com/salestools/NRAN-6CN8PK_R0_EN.pdf

◦ Christian Belady – http://electronics-cooling.com/articles/2007/feb/a3/

◦ Dell – http://www.dell.com/downloads/global/power/ps1q07-20070210-CoverStory.pdf

◦ Intel – http://www.intel.com

25