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Parasol and GreenSwitch : Managing Datacenters Powered by Renewable Energy. Íñigo Goiri , William Katsak , Kien Le, Thu D. Nguyen, and Ricardo Bianchini Department of Computer Science . Motivation. Datacenters consume large amounts of energy High energy cost and carbon footprint
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Parasol and GreenSwitch:Managing Datacenters Powered by Renewable Energy ÍñigoGoiri, William Katsak, Kien Le, Thu D. Nguyen, and Ricardo Bianchini Department of Computer Science
Motivation • Datacenters consume large amounts of energy • High energy cost and carbon footprint • Brown electricity: coal and natural gas • Connect datacenters to green sources: solar, wind Apple DC in Maiden, NC 40MW solar farm Green datacenter
Challenges and opportunities • Scheduling workload/energy sources • Lower costs: brown energy, peak brown power, capital • Study opportunities in green datacenters • Build hardware/software Solar power Variable Storage? Power Load Workload Time Source?
Outline • Motivation • Parasol • Solar-powered micro-datacenter • GreenSwitch • Manage workload and energy sources • GreenSwitch results • Conclusion
Parasol 16 solar panels: 3.2kW 2 inverters: DC→AC 16 lead-acid batteries: 32kWh 2 charge controllers: Off-grid, DC↔AC http://parasol.cs.rutgers.edu • Installed on the roof • Steel structure • Small container • IT equipment • 2 racks • 64 Atom servers • 2 switches • 3 PDUs
Electrical infrastructure Inverter DC AC Electrical Panel AC AC Charge Controller AC Power grid DC IT Equipment
Example energy source management Power Inverter DC Time AC Electrical Panel AC AC Charge Controller AC Power grid DC IT Equipment
Example energy source management Power Inverter DC Time AC Electrical Panel AC AC Charge Controller AC Power grid DC IT Equipment
Example energy source management Power Inverter DC Time AC Electrical Panel AC AC Charge Controller AC Power grid DC IT Equipment
Possible energy source management Basic • Each time slot: • Weather conditions • Brown energy price • Peak brown power price • Battery charge level • Active servers • Workload slack Power Time Maximizing benefits is complex
GreenSwitch • Minimize brown electricity cost • Brown energy • Peak brown power • Battery lifetime constraint • Manage energy sources • Use solar/net metering • Charge/discharge battery • Limit brown peak power • Manage workload • Turn servers on/off • Delay deferrable jobs Get status Perform changes
GreenSwitch architecture GreenSwitch Battery Charge Level Energy Source Schedule Solver Configurer Power Power Workload Prediction Workload Schedule Predictor Time Time Model & MILP Energy Availability Prediction Workload Solar Workload Brown Price Parasol Use solar to power all servers Charge battery with surplus solar
Experimental environment • Evaluation on 64 Parasol nodes • 12 one-day experiments • Deferrable vs. non-deferrable workloads • Baseline datacenter (no solar, no batteries, no delays) • New Jersey brown electricity pricing • On/off-peak energy, peak power, net metering • GreenSwitch for Hadoop (configurer)
Experimental environment IT load • SWIM: Facebook based workload [MASCOTS’11]
Parasol without GreenSwitch Green available Net metering IT load Green use Brown use 66% cost savings → Solar amortized in 7 years
GreenSwitch: non-deferrable workload Green available Battery charge Battery discharge IT load Peak grid power Green use Brown use 75% cost savings → Batteries cannot be amortized
GreenSwitch: deferrable workload Green available Net metering Battery charge IT load Battery discharge Green use 96% cost savings → Solar + batteries amortized in 7.6 years
Parasol: a real system • Real software running on real hardware • Power losses • Overhead of energy source switching • System limitations • Net metering vs. Battery charging • Use brown vs. Net metering • Green battery charging vs. Use brown
Conclusions • Green datacenters • Challenges & opportunities • Hardware/software solution • GreenSwitchbenefits • Delaying load and solar gives the best results • Reduces amortization time by 1.8-2x • Flexibility: no batteries, workloads, wind… http://parasol.cs.rutgers.edu
Parasol and GreenSwitch:Managing Datacenters Powered by Renewable Energy ÍñigoGoiri, William Katsak, Kien Le, Thu D. Nguyen, and Ricardo Bianchini http://parasol.cs.rutgers.edu
Fewer conversions • Grid-tie: AC→DC • Low conversion losses • Commodity hardware • Availability • Cheaper • Cheaper transmission
Parasol: lessons learned • Not cheap • Flexibility adds complexity and cost • Placement on the roof • Full monitoring • Not easy • Complete design • Dealing with facilities, companies, and vendors • Mistakes are easy • Delays, delays, and more delays
Viability of green datacenters • Example companies investing in self-generation • Apple, Microsoft, McGraw-Hill • Research shows cost savings • Getting more attractive • Space: Solar panels are getting more efficient • Cost: 7x cheaper than 30 years ago • Governmental Incentives • Grid-centric: power purchase agreement • Losses, dependence, long term scalability
Other results • Energy storage • Batteries • Net metering pricing • Peak grid power charges • Solar availability • Cloudy, sunny, rainy… • Other workloads • Nutch • Grid outage