Impact of the distribution quality of file replicas on replication strategies

Data grids provide scalable infrastructures for storage resources and data files management and support data-intensive applications. These applications require to efficiently access, store, transfer and analyze a large amount of data in geographically distributed locations around the world. Data replication is a key technique used in data grids to achieve these goals through creating multiple file replicas and placing them in a wisely manner. In this context, several replication strategies were proposed in the literature. The main idea of our work is to propose a new aspect of the evaluation of replication strategies which is the quality assessment of replicas placement in the data grid. This paper will indeed prove the impact of the distribution on the evaluation results. We hence show the importance of evaluating the quality of the replicas distribution in the data grid. Then, we propose evaluation processes of the quality of a given distribution. In this respect, different evaluation metrics are proposed for assessing the performances of replication strategies with respect to the distribution quality. We will also evaluate our metrics by using the OptorSim simulator and perform extensive experiments that will prove the effectiveness of our contributions.