Measuring and analyzing the energy use of enterprise computing systems Xiuming Zhang

System Deployment Powernet: a hybrid sensor network that monitors the power and utilization of the IT systems in a large academic building Over more than two years 250+individual computing devices One power meter per device

Appliance Types Measured

Extrapolating to the Whole Building

Power Share by Type 4 types: PC, LCD, server, switch

PC Binned into 3 categories – Laptops – Low-end – High-end 742 in total – 456: description available. The other: assume same distribution.

LCD

Lower brightness & use dark backgrounds

Server Monitors 32 of the 500 servers Calculated average power: 233 W Estimated total power of 500 servers: 117 kW

Switch

PC CPU Utilization 95% of the computers have a utilization rate lower than 30%

Popular Workloads

Network Switch Utilization The demand never exceeded 200 Mbps

Network Switch Utilization Highly underutilized Total network demand < 1000 Mbps 100% of the time.

Discussions

How does the sampling frequency affect what the data reveal? Too small  hide the anomalies

How big is the variance between two instances of same model?

Does sampling a few devices provide an accurate average measurement? shows the wide distribution of desktop power

Does sampling a few devices provide an accurate average measurement? Large sample size desired for PC 1,000,000 random samples of size 5, 10, and 20, drawing from 69 machines

Do short-term measurements accurately reflect long-term power draw? One-month scale yields an acceptable error

Are Energy Star data representative? Energy Star Standard does not consider PCs under load

Thanks for the attention!