parasol and greenswitch: managing datacenters powered by renewable energy Íñigo goiri, william...
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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
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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
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Challenges and opportunities
• Scheduling workload/energy sources– Lower costs: brown energy, peak brown power, capital
• Study opportunities in green datacenters– Build hardware/software
Power
Time
Load
VariableSolar power
Workload
Source?
Storage?
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Outline
• Motivation• Parasol– Solar-powered micro-datacenter
• GreenSwitch– Manage workload and energy sources
• GreenSwitch results• Conclusion
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Parasol16 solar panels: 3.2kW2 inverters: DC→AC
Installed on the roof• Steel structure• Small container
IT equipment• 2 racks• 64 Atom servers• 2 switches• 3 PDUs
16 lead-acid batteries: 32kWh2 charge controllers: Off-grid, DC↔AC
http://parasol.cs.rutgers.edu
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Electrical infrastructure
Charge Controller
Inverter
Electrical Panel
DC
AC
AC
DC
AC
Power grid
AC
IT Equipment
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Example energy source management
Charge Controller
Inverter
Electrical Panel
DC
AC
AC
DC
AC
Power grid
AC
Time
Pow
erIT Equipment
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Example energy source management
Charge Controller
Inverter
Electrical Panel
DC
AC
AC
DC
AC
Power grid
AC
Time
Pow
erIT Equipment
9
Example energy source management
Charge Controller
Inverter
Electrical Panel
DC
AC
AC
DC
AC
Power grid
AC
Time
Pow
erIT Equipment
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Possible energy source management
Pow
er
Time
Basic
Maximizing benefits is complex
Each time slot:• Weather conditions• Brown energy price• Peak brown power price• Battery charge level• Active servers• Workload slack
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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
Parasol
GreenSwitch
Perform changesGet status
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GreenSwitch
GreenSwitch architecture
Predictor
Battery Charge Level
Workload Prediction
Energy Availability Prediction
Solver
Energy Source Schedule
Workload Schedule
Configurer
Parasol
TimePo
werBrownPrice
Solar
Time
Pow
er
Workload
Use solar to power all serversCharge battery with surplus solar
Workload
Model & MILP
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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)
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Experimental environment
SWIM: Facebook based workload [MASCOTS’11]
IT load
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Parasol without GreenSwitch
Green use
Green available
Net metering
Brown use
IT load
66% cost savings → Solar amortized in 7 years
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GreenSwitch: non-deferrable workload
Battery dischargeBattery chargeIT load
75% cost savings → Batteries cannot be amortized
Peak grid power
Green use Brown use
Green available
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GreenSwitch: deferrable workload
Battery discharge
Battery charge
IT load
Net metering
96% cost savings → Solar + batteries amortized in 7.6 years
Green available
Green use
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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
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Conclusions
• Green datacenters– Challenges & opportunities– Hardware/software solution
• GreenSwitch benefits– 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
Íñigo Goiri, William Katsak, Kien Le,Thu D. Nguyen, and Ricardo Bianchini
http://parasol.cs.rutgers.edu
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• Fewer conversions– Grid-tie: AC→DC
• Low conversion losses
• Commodity hardware– Availability– Cheaper
• Cheaper transmission
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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
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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
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Other results
• Energy storage– Batteries– Net metering pricing
• Peak grid power charges• Solar availability– Cloudy, sunny, rainy…
• Other workloads– Nutch
• Grid outage