An Approach Based on Market Economy for Consistency Management in Data Grids with Optorsim Simulator

Abstract

Data Grids are currently solutions suggested to meet the needs of scale large systems. They provide highly varied and geographically distributed resources of which the goal is to ensure fast and effective data access. This improves availability, and tolerates breakdowns. In such systems, these advantages are not possible without the use of replication. The use of the technique of replication poses a problem in regards to the maintenance of the consistency of the same data replicas; the strategies of replication of the data and scheduling of jobs were tested by simulation. Several grid simulators were born. One of the most interesting simulators for this study is the OptorSim tool. In this chapter, the authors present an extension of the OptorSim by a consistency management module of the replicas in Data Grids; they propose a hybrid step which combines the economic models conceived for a hierarchical model with two levels. This suggested approach has two vocations, the first allowing a reduction in response times compared to an pessimistic approach, the second gives the good quality of service compared to optimistic approach.