Time- and Cost- Efficient Task Scheduling across Geo-Distributed Data Centers

Abstract

Typically called big data processing, analyzing large volumes of data from geographically distributed regions with machine learning algorithms has emerged as an important analytical tool for governments and multinational corporations. The traditional wisdom calls for the collection of all the data across the world to a central data center location, to be processed using data-parallel applications. This is neither efficient nor practical as the volume of data grows exponentially. Rather than transferring data, we believe that computation tasks should be scheduled near the data, while data should be processed with a minimum amount of transfers across data centers. In this paper, we design and implement Flutter, a new task scheduling algorithm that reduces both the completion times and the network costs of big data processing jobs across geographically distributed data centers. To cater to the specific characteristics of data-parallel applications, in the case of optimizing the job completion times only, we first formulate our problem as a lexicographical min-max integer linear programming (ILP) problem, and then transform the ILP problem into a nonlinear program problem with a separable convex objective function and a totally unimodular constraint matrix, which can be further solved using a standard linear programming solver efficiently in an online fashion. In the case of improving both time-and costefficiency, we formulate the general problem as an ILP problem and we find out that solving an LP problem can achieve the same goal in the real practice. Our implementation of Flutter is based on Apache Spark, a modern framework popular for big data processing. Our experimental results have shown convincing evidence that Flutter can shorten both job completion times and network costs by a substantial margin.