A two phased service oriented Broker for replica selection in data grids

Replica selection is one of the fundamental problems in Data Grid’s environment. This work’s concern is designing a Two phasedService Oriented Broker (2SOB) for replica selection. It is focused on investigating, selecting, modifying, and experimenting with some non-conventional approaches to be applied on the relevant selection techniques. The motivation of this work is to introduce a novel Service OrientedBroker for Replica Selection in Data Grid. The main characteristics of this 2SOB are: Scalability, Reliability, Availability, Efficiency and Ease of deployment. 2SOB consists of two phases; the first is a Coarse-grainphase, basically used for sifting replica sites that have low latency (uncongested network links) and distinguishing them from other replicas having a high latency (congested network links). Procedurally, this has been done using the association rules concept of the Data Mining approach. The second is a Fine-grainphase,used for extracting the replicas admissible for user requirements through applying Modified Minimum Cost and Delay Policy (MMCD). Both phases have accordingly been designed, simulated, coded, and then validated using real data from EU Data Grid.The first phase has thereby been applied on the real network data of CERN (February 2011). Experimentations compared with some other contemporary selection methods of different Brokers showed appreciable results. Using this proposed Broker it is possible to achieve an enhancement in the speed of executing Data Grid jobs through reducing the transfer time.

► Scalability: A scalable Broker is designed using Efficient Set Technique EST. ► Reliability and availability: Using EST there is no possibility of non-existence of the file(s) in the selected sites. ► Transmission efficiency: Number of stable provider sites are ready to be used with a single run of EST. ► Easy to deploy: EST works within the existing Data Grid infrastructure.