Objective assessment of the performance of data grid replication strategies based on distribution quality

Abstract

Replication is an important issue for the data grid performance. Indeed, it has for main purposes to improve data access efficiency, provide high availability, decrease bandwidth consumption, improve fault tolerance and enhance scalability. In this regard, where to place a given replica represents an important step in a replication process. In this context, a significant number of placement strategies has been proposed in the literature. Each placement strategy produces a specific replicas distribution through the grid sites. This distribution will directly affect the performance of the grid. In this paper, we propose a new evaluation metric called the distribution quality, and denoted DisQ. This metric quantifies, at a given point in time, the quality of a given distribution of replicas through the grid nodes. DisQ helps to know beforehand that a given distribution will contribute in obtaining interesting data grid performance or it will degrade them. Using DisQ, we propose a correction for the evaluation metrics of replication strategies to make them more reliable. We use the OptorSim simulator to validate our theoretical contributions.