A Utility-Based Data Replication Algorithm in Large Scale Data Grids

Abstract

<em>Data grids support access to widely distributed storage for large numbers of users accessing potentially many files. To enhance access time, replication at nearby sites may be used. Data replication, a technique much investigated by</em><em>data grid researchers in past years creates multiple replicas of</em><em>file and places them in conventional locations to shorten file</em><em>access times. One of the problems in data replication is</em><em>creation of replicas, replica placement and replica selection. Dynamic creation of replicas in an appropriate site by data</em><em>replication strategy can increase the systems performance.</em><em>In this paper, we propose a data replication algorithm, called the Utility-base Data Replication (UDR) algorithm that improves file access time. Each grid site has its own capabilities and characteristics; therefore, choosing one specific site from many sites that have the needed data is a key and significant decision. The replica selection problem has been studied by many researchers who only considered response time as a criterion for the selection process. Therefore, in this study, we addressed the problem of how to select the best replica for the users' jobs. Our approach is simulated using a data grid simulator, OptorSim, developed by European Data Grid projects. Comparing to the previous work the experimentation shows the improvement in the overall performance.</em>