Nowadays, datagrids can be seen as frameworks responding to the needs of large scale applications by affording so many resources. These are distributed on different geographically locations, but are organized to prov...
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Nowadays, datagrids can be seen as frameworks responding to the needs of large scale applications by affording so many resources. These are distributed on different geographically locations, but are organized to provide an integrated service. This paper studies replica placement in hierarchical data grid systems taking into account the following important issue: The hierarchical data grid can be presented as a tree structure. This structure will be labeled by a new labeling scheme (called Dewey Encoding) that lies at the core of query processing for many XML databases. This scheme avoids unnecessary replications and achieves good performance by balancing the load of replica servers. The good performance of the proposed algorithm is based on minimizing the Mean Job Execution time and Network utilization. (C) 2014 Published by Elsevier Ltd.
The datagrid, as a specialization and extension of the grid, has been adopted as the solution to solve data-intensive problems, such as high energy physics, life science and etc. Large data files are replicated acros...
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The datagrid, as a specialization and extension of the grid, has been adopted as the solution to solve data-intensive problems, such as high energy physics, life science and etc. Large data files are replicated across the datagrid to improve the system performance. One form of the datagrid studied is the hierarchical data grid used in LHC experiments. There has been a lot of research work on replication algorithms for the hierarchical data grid. It is important and useful to analyze the optimal performance, as it can be used as a benchmark to compare the performances of different replication algorithms and helps us to understand how good the replication algorithms are in approaching the optimal performance. In this paper, we construct a model to predict the optimal performance of the hierarchical data grid. The performance metrics used for the model are average response time and average bandwidth cost. We propose the optimal replication algorithm and present a detailed analysis of its performance. The Multi-Tier datagrid is used as a specific example of the hierarchical data grid to verify our model. The performance of the proposed optimal replication algorithm is studied together with three well-known replication algorithms. The simulation results show that the optimal replication algorithm has the best performance and its performance is pretty close to the result obtained using our probabilistic model. (C) 2009 Elsevier B.V. All rights reserved.
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