# Presentation: 070503

## Data center power use: a review of the historical data

- Jonathan G. Koomey, Ph.D.
- LBNL and Stanford University
- JGKoomey@lbl.gov, JGKoomey@stanford.edu
- http://datacenters.lbl.gov
- Presented at the IBM Austin Conference on Energy-Efficient Design
- Austin, TX
-  March 2, 2004

**Notes:**
Purpose of talk is to get present results of our work with the Uptime Institute folks in aggregating their data, and to get your feedback.  I want this session to be interactive.

## Background	

- Continued controversy over how much power is used by computers and data centers in particular (see http://enduse.lbl.gov/Projects/InfoTech.html)
- Many claims of 100, 200, 300 Watts/square foot for planned data center facilities circa 1999-2001
- Are these numbers representative of hosting facilities generally?
- Are they representative of corporate data centers?

## Data sources

- For power densities
- Mitchell Jackson 2001–same facility revisited (2003)
- LBNL Benchmarking results
- Uptime Institute (with permission)
- For efficiency opportunities
- RMI data center charrette

## Data center in Bay Area--Mitchell Jackson 2001, revisited in 2003

- Detailed assessment of a single facility in 2001 (we had complete access)
- Revisited same facility in 2003
- Data center floor area up 33%
- Total computer power density (W/sf) up 13%
- Total computer room power density (in W/sf, including HVAC and auxiliaries) constant 2001 to 2003
- Removing unnecessary lighting and CRAC units plus HVAC adjustments led to significant savings

## Data center in Bay Area:power densities

## Data center in Bay Area: more on power densities

- Source for 2003 data: Blazek, Michele, Huimin Chong, Woonsien Loh, and Jonathan Koomey. 2004. "A data center revisited: Assessment of the energy impacts of retrofits and technology trends in a high-density computing facility."
*Forthcoming in a special issue of the ASCE Journal of Infrastructure Systems*. January.
- Source for 2001 data: Mitchell-Jackson, Jennifer, Jonathan Koomey, Bruce Nordman, and Michele Blazek. 2003. "Data Center  Power Requirements: Measurements From Silicon Valley." *Energy–The International Journal (also LBNL-48554)*. vol. 28, no. 8. June. pp. 837 - 850.

## LBNL case studies

- 14 Data centers in California and New York
- Detailed metering and analysis of facilities
- Led by Bill Tschudi and Dale Sartor of LBNL
- 2d phase of benchmarking activities just begun, seeking new facilities!

## LBNL benchmarking results: Computer power densities

- Average 39.3

- Average ~25

## Slide 9

## Uptime Institute data:  Methods

- Obtain data from Site Uptime Network data on a confidential basis
- Analyze responses to Network quarterly profile questionnaires for 1999, 2000, and 2001
- Focus on UPS power and electrically active (net) floor area in square feet (sf)
- Clean data, eliminating inconsistencies in reporting, typos, and other problems
- Summarize data in averages and in cumulative distributions

## Uptime Institute data:  Results

- Distributions don’t differ much over the three year analysis period
- Minimum computer room power densities are 8-10 W/sf, maximums are 70-80 W/sf, avg is 22-25 W/sf
- To get total loads (HVAC & auxiliaries plus electrically active floor area power use) multiply by about 2, yielding average total power densities of roughly 50 W/sf (comparable to previous estimates)
- No obvious time trends in the data, either in the aggregate or when examined by facility

## Distribution of Computer Room Power Used by Site Uptime Network Data Centers

## Uptime Institute data: Summary

- On average, Network facilities show computer room power densities (electrically-active floor area) of 22-25 W/sf (total power densities ~ 50 W/sf, consistent with earlier work)
- Maximum computer power density in sample is 70-80W/sf, minimum is 8-10 W/sf
- Sample size not enough to determine time trends or to draw conclusions by industry type
- More work needed to estimate total data center floor area in the US and total power demands

## Efficiency opportunities

- Lighting
- HVAC
- Servers
- Power supplies (some now only 50% efficient)
- Dynamic processor power management using voltage and frequency scaling (e.g., IBM Power PC 405 LP, Transmeta)
- Optimization at any point in the design process fails to account for whole system effects (e.g. servers)
- Need to align incentives (charge per kW of power demanded in data center facilities, not per square foot)

## Efficiency opportunities:  RMI Charrette results (Feb 2003)

- For details, see http://www.rmi.org/sitepages/pid626.php

## Conclusions

- Consistent definitions are critical
- Typical data center computer power densities are roughly 25 W/sf, implying total computer room power densities of roughly 50 W/sf
- Few isolated examples of computer power densities greater than 80 W/sf
- More data needed
- larger sample size
- data for same facilities over time
- Not clear that expectations of much higher power densities will come to pass
- Plenty of empty space to spread out servers
- Large efficiency opportunities

## A widely circulated forecast

- Source:  Uptime Institute

## New IBM Class:  Getting the numbers right http://www.numbersintoknowledge.com

- Training class in compiling, analyzing, and presenting numbers for effective decision-making to be taught at the IBM Performance Testing Center in San Jose, CA March 29-31, 2004.  Course will be generally available throughout IBM after that.