Grid computing is a type of distributed computing system that provides access to various computational resources which are shared by different organizations, in order to create an integrated powerful virtual computer. Nowadays, grid is known as an essential technology which is used for different kinds of high performance applications and it is believed that it will be applied more and more in the future as technology progresses. Data replication is a common method used in distributed environments to improve ease of data access and to provide a high level of data availability, increased fault tolerance and data reliability; and that’s why this method is used for data management in data grid systems. Since the data files are very large and the Grid storages are limited, managing replicas in storage for the purpose of more effective utilization requires more attention. In this paper, a novel data replication strategy, called Replication with Dynamic Threshold (RDT) is proposed that uses a new threshold for characterizing the number of appropriate sites for replication. Appropriate sites have the higher number of access for that particular replica from other sites. It also minimizes access latency by selecting the best replica when various sites hold replicas. The simulated results with OptorSim, i.e. European Data Grid simulator show that the RDT strategy gives better performance compared to the other algorithms and prevents the unnecessary creation of replicas which leads to efficient storage usage.

Distributed systems; Data grid; Data replication; Dynamic Threshold; OptorSim

[1] M. Li and M. Baker, “The grid core technologies”, John Wiley & Sons, 2005.
[2] N. Mohd. Zin, A. Noraziah, A. Che Fauzi, and T. Herawan, “Replication Techniques in Data Grid Environments”, in Intelligent Information and Database Systems, vol. 7197, Eds. Springer Berlin, Heidelberg, pp. 549–559, 2012.
[3] K. Ranganathan and I. Foster, “Decoupling computation and data scheduling in distributed data-intensive applications”, in 11th IEEE International Symposium on High Performance Distributed Computing, pp. 352–358, 2002.
[4] K. Sashi and A.S. Thanamani, “A new replica creation and placement algorithm for data grid environment”, in International Conference on Data Storage and Data Engineering (DSDE), pp. 265–269, 2010.
[5] S. Naseera and K.V.M. Murthy, “Agent Based Replica Placement in a Data Grid Environement”, in First International Conference on Computational Intelligence, Communication Systems and Networks, pp. 426–430, 2009,.
[6] F.B. Charrada, H. Ounelli, and H. Chettaoui, “Dynamic period vs static period in data grid replication”, in International Conference on P2P, Parallel, Grid, Cloud and Internet Computing (3PGCIC), pp. 565–568, 2010.
[7] W. Hoschek, J. Jaen-Martinez, A. Samar, H. Stockinger, and K. Stockinger, “Data management in an international data grid project”, in Grid Computing, Springer, pp. 77–90, 2000.
[8] A. Chervenak, I. Foster, C. Kesselman, C. Salisbury, and S. Tuecke, “The data grid: Towards an architecture for the distributed management and analysis of large scientific datasets”, in Network Computing Application, vol. 23, no. 3, pp. 187–200, 2000.
[9] I. Foster and C. Kesselman, “The Grid 2: Blueprint for a New Computing Infrastructure”, Morgan Kaufmann, 2003.
[10] S. Venugopal, R. Buyya, and K. Ramamohanarao, “A taxonomy of data grids for distributed data sharing, management, and processing”, in Acm Computing Surveys, vol. 38, no. 1, p. 3, 2006.
[11] M. Mat Deris, J.H. Abawajy, and A. Mamat, “An efficient replicated data access approach for large-scale distributed systems”,in Future generation computer systems, vol. 24, no. 1, pp. 1–9, 2008.
[12] H. Lamehamedi, B. Szymanski, Z. Shentu, and E. Deelman, “Data replication strategies in grid environments”, in Fifth International Conference on Algorithms and Architectures for Parallel Processing, pp. 378 –383, 2002.
[13] K. Ranganathan, A. Iamnitchi, and I. Foster, “Improving data availability through dynamic model-driven replication in large peer-to-peer communities”, in 2nd IEEE/ACM International Symposium on Cluster Computing and the Grid, pp. 376–376, 2002.
[14] S. Goel and R. Buyya, “Data replication strategies in wide area distributed systems”, in Enterprise Service Computing: From Concept to Deployment, vol. 17, 2006.
[15] R. Buyya, D. Abramson, and J. Giddy, “An architecture for a resource management and scheduling system in a global computational grid”, in The Fourth International Conference/Exhibition on High Performance Computing in the Asia-Pacific Region, vol. 1, pp. 283–289, 2000.
[16] I. Foster, C. Kesselman, and S. Tuecke, “The Anatomy of the Grid: Enabling Scalable Virtual Organizations”, in International Journal of High Performance Computing Applications, vol. 15, no. 3, pp. 200–222, 2001.
[17] K. Ranganathan and I. Foster, “Identifying dynamic replication strategies for a high-performance data grid”, Grid Computing, pp. 75–86, 2001.
[18] M. Tang, B.S. Lee, C.K. Yeo, and X. Tang, “Dynamic replication algorithms for the multi-tier Data Grid”, in Future Generation Computer Systems, vol. 21, no. 5, pp. 775–790, 2005.
[19] K. Sashi and A.S. Thanamani, “Dynamic replication in a data grid using a Modified BHR Region Based Algorithm”, in Future Generation Computer Systems, vol. 27, no. 2, pp. 202–210, 2011.
[20] J. Gwertzman, “M. seltzer: The Case for Geographical Push-Cashing,” in 5th Conference on Hot Topics in Operating systems, Orcas Island, USA, 1995.
[21] D.G. Cameron, R. Carvajal-Schiaffino, A.P. Millar, C. Nicholson, K. Stockinger, and F. Zini, “OptorSim: a grid simulator for replica optimisation”, in UK e-science all hands conference, vol. 31, 2004.
[22] J. Abawajy, “Placement of File Replicas in Data Grid Environments”, in Computational Science ( ICCS), vol. 3038, Springer Berlin, Heidelberg, pp. 66–73, 2004.
[23] S.M. Park, J.H. Kim, Y.B. Ko, and W.S. Yoon, “Dynamic data grid replication strategy based on Internet hierarchy”, in Grid and Cooperative Computing, pp. 838–846, 2004.
[24] R.M. Rahman, K. Barker, and R. Alhajj, “Replica placement design with static optimality and dynamic maintainability”, in Sixth IEEE International Symposium on Cluster Computing and the Grid (CCGRID), vol. 1, pp.4, 2006.
[25] R.M. Rahman, K. Barker, and R. Alhajj, “Replica placement in data grid: a multi-objective approach”, in Grid and Cooperative Computing (GCC), Springer, pp. 645–656, 2005.
[26] W. Zhao, X. Xu, N. Xiong, and Z. Wang, “A weight-based dynamic replica replacement strategy in data grids”, in IEEE Asia-Pacific Services Computing Conference,(APSCC), pp. 1544–1549, 2008.
[27] R.S. Chang and H.P. Chang, “A dynamic data replication strategy using access-weights in data grids”, in The Journal of Supercomputing, vol. 45, no. 3, pp. 277–295, 2008.
[28] M. Shorfuzzaman, P. Graham, and R. Eskicioglu, “Adaptive popularity-driven replica placement in hierarchical data grids”, in The Journal of Supercomputing, vol. 51, no. 3, pp. 374–392, 2010.
[29] F.B. Charrada, H. Ounelli, and H. Chettaoui, “An efficient replication strategy for dynamic data grids”, in International Conference on P2P, Parallel, Grid, Cloud and Internet Computing (3PGCIC), pp. 50–54, 2010.
[30] W. Zhao, X. Xu, Z. Wang, Y. Zhang, and S. He, “Improve the performance of data grids by value-based replication strategy”, in Sixth International Conference on Semantics Knowledge and Grid (SKG), pp. 313–316, 2010.
[31] M. Bsoul, A. Al-Khasawneh, E.E. Abdallah, and Y. Kilani, “Enhanced fast spread replication strategy for data grid”, in Journal of Network and Computer Applications , vol. 34, no. 2, pp. 575–580, 2011.
[32] L.M. Khanli, A. Isazadeh, and T.N. Shishavan, “PHFS: A dynamic replication method, to decrease access latency in the multi-tier data grid”, in Future Generation Computer Systems, vol. 27, no. 3, pp. 233–244, 2011.
[33] N. Mansouri and G.H. Dastghaibyfard, “A dynamic replica management strategy in data grid”, in Journal of Network and Computer Applications, vol. 35, no. 4, pp. 1297–1303, 2012.
[34] N. Mansouri, “An Effective Weighted Data Replication Strategy for Data Grid”, in Australian Journal of Basic and Applied Sciences, vol. 6, no. 10, pp. 336–346, 2012.
[35] W. H. Bell, D. G. Cameron, R. Carvajal-Schiaffino, A. P. Millar, K. Stockinger, and F. Zini, “Evaluation of an Economy- Based File Replication Strategy for a Data Grid”, in Proc. Of 3rd IEEE Int. Symposium on Cluster Computing and the Grid (CCGrid), Tokyo, Japan, IEEE CS-Press, 2003.
[36] A. Horri, R. Sepahvand, and G. Dastghaibyfard, “A hierarchical scheduling and replication strategy”, International Journal of Computer Science and Network Security- IJCSNS, vol. 8, no. 8, pp. 30–35, 2008.
[37] D. G. Cameron, “OptorSim v2.1 Installation and User Guide”, User Guide, University of Glasgow, Scotland, 2006.