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胡秩瑋. Minimizing Electricity Cost: Optimization of Distributed Internet Data Centers in a Multi-Electricity-Market Environment. Overview. INTRODUCTION RELATED WORK FORMULATION AND MODELING SOLUTION METHOD DESIGN
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胡秩瑋 Minimizing Electricity Cost: Optimization of Distributed Internet Data Centers in a Multi-Electricity-Market Environment
Overview • INTRODUCTION • RELATED WORK • FORMULATION AND MODELING • SOLUTION METHOD DESIGN • ELECTRICITY PRICE AT CERTAIN LOCATIONS FOR GOOGLE INTERNET DATA CENTERS • PERFORMANCE EVALUATION • CONCLUSION AND FUTURE WORK
INTRODUCTION • As the developing of cloud computing, there are more and more Internet Data Centers(IDCs). • IDC demands a lot of power, it means that it costs much money. • The goal of this paper is to minimize the cost of IDCs while guaranteeing quality of service.
INTRODUCTION • Authors achieve the goal with linear programming and polynomial-time method. • The evaluations are based on real-life electricity price data.
FORMULATION AND MODELINGTotal Electricity Cost Modeling for IDC • Two assumption: 1. The power consumption profile is constant for every server. 2. Each server at the same location receives the same traffic rate in steady-state.
FORMULATION AND MODELINGTotal Electricity Cost Modeling for IDC • Thus, the total electricity cost for N data center location is: i:IDC location :the number of turned on servers at i :Spot price of electricity at i:power consumption for one server at i
FORMULATION AND MODELINGWorkload Constraint Modeling • We model the workload constraints in order to capture the requests allocations among all the data center locations for each front-end Web portal. • We have: :the requests demand at each front-end Web portal server j (j=1,…,C) C :total number of front-end Web portal servers :the request arrival rate from front-end Web portal server j to locationi
FORMULATION AND MODELINGDelay Constraint Modeling • At location i with servers, when each server has the service rate and the total arrival rate is , the average delay is given as = • : service rate
FORMULATION AND MODELINGFormulation of Total Electricity Cost Minimization Problem • The objective function(problem one):
SOLUTION METHOD DESIGN • We are going to present a solution method for problem one in this section. • We approximate the problem by linear programming and solve it with polynomial-time algorithm.
SOLUTION METHOD DESIGNMixed Integer Linear Programming Formulation • First of all, we rewrite the problem one as: subject to: • .
SOLUTION METHOD DESIGNMixed Integer Linear Programming Formulation • As must be integer, we can transform Problem1 to Problem2: Subject to , = ,
SOLUTION METHOD DESIGNPolynomial-Time Solution for Approximated Total Electricity Cost Minimization Problem • In this subsection, we show that Problem Two can be converted to a minimum cost flow problem. • we consider a simple case that N =3 and C = 5.
SOLUTION METHOD DESIGNPolynomial-Time Solution for Approximated Total Electricity Cost Minimization Problem Subject to λ11 + λ12 + λ13 = L1, λ21 + λ22 + λ23 = L2, λ31 + λ32 + λ33 = L3, λ41 + λ42 + λ43 = L4, λ51 + λ52 + λ53 = L5, λ11 + λ21 + λ31 + λ41 + λ51 λ12 + λ22 + λ32 + λ42 + λ52 ≤ λ13 + λ23 + λ33 + λ43 + λ53 ≤ Total workload from 5 web servers Maximum workload that all locations can afford
ELECTRICITY PRICE AT CERTAIN LOCATIONS FOR GOOGLE INTERNET DATA CENTERS California : hour-ahead market Texas : 15-min ahead market Atlanta : fixed electricity rate
ELECTRICITY PRICE AT CERTAIN LOCATIONS FOR GOOGLE INTERNET DATA CENTERS
PERFORMANCE EVALUATION Average electricity cost of request processing: : Average electricity cost of upper limitation number of servers: :