Research And Realization On Distributed Replica Location In Data Grids

Data Grid architecture provides a large-scale, scalable infrastructure for the management of storage resources and data that are distributed across grid environments. Based on the requirements to data sharing and managing of data-intensive computing application, it provides the mechanisms for transparently remote accessing to heterogeneous data resources. Replica management is one of the critical parts in data grids. The replica created could reduce the network delay and bandwidth consumes when accessing to the data and improves load balance of network. It could also improve security, reliability and system tolerance of the data. Excellent replica management strategies are important to improve the QoS in data grids. Replica management strategies include replicas creation strategies, replicas selection strategies and replicas location mechanism and so on. Replica location mechanism is an important tache in improving performance of the system. This paper investigates on replica location strategies of replica management in data grids and the main work are as follows:1. A PM-Chord (Prefix Matching-Chord) method which improves and expands a replica location strategy based on Chord theory in P2P field is proposed in this paper by studying some replica location strategies exist. PM-Chord has the following new features.(1) Change the method of the data storage and separate the node search and data search which use prefix matching principle based on binary search.(2) Add the predecessor replication mechanism to solve the hot spots question in data grids and improve the reliability of the system.2. Realized PM-RLS which use PM-Chord method as replica location strategy on the Globus basis. Analysis and experiments show that not only PM-Chord has better performance than Chord at the replica location and can achieve reliability, stability.