Algorithms for Energy Conservation in Heterogeneous Data Centers

TL;DR

This paper develops and analyzes online algorithms for energy-efficient management of heterogeneous data centers, providing optimal and near-optimal solutions with proven competitive ratios.

Contribution

It introduces deterministic and randomized online algorithms for right-sizing heterogeneous data centers, achieving optimal and near-optimal competitive ratios.

Findings

Deterministic algorithm is proven to be optimal with ratio 2d.

Randomized algorithm achieves a ratio of 1.58d.

No deterministic algorithm can have a ratio smaller than 2d.

Abstract

Power consumption is the major cost factor in data centers. It can be reduced by dynamically right-sizing the data center according to the currently arriving jobs. If there is a long period with low load, servers can be powered down to save energy. For identical machines, the problem has already been solved optimally by Lin et al. (2013) and Albers and Quedenfeld (2018). In this paper, we study how a data-center with heterogeneous servers can dynamically be right-sized to minimize the energy consumption. There are $d$ different server types with various operating and switching costs. We present a deterministic online algorithm that achieves a competitive ratio of $2d$ as well as a randomized version that is $1.58d$-competitive. Furthermore, we show that there is no deterministic online algorithm that attains a competitive ratio smaller than $2d$. Hence our deterministic algorithm is optimal. In contrast to related problems like convex body chasing and convex function chasing, we investigate the discrete setting where the number of active servers must be integral, so we gain truly feasible solutions.