An Approach Based on Market Economy for Consistency Management in Data Grids with Optorsim Simulator

An Approach Based on Market Economy for Consistency Management in Data Grids with Optorsim Simulator

Ghalem Belalem, Belabbes Yagoubi, Samah Bouamama
DOI: 10.4018/978-1-60566-719-5.ch016
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Data Grids are currently solutions suggested to meet the needs of scale large systems. They provide highly varied and geographically distributed resources of which the goal is to ensure fast and effective data access. This improves availability, and tolerates breakdowns. In such systems, these advantages are not possible without the use of replication. The use of the technique of replication poses a problem in regards to the maintenance of the consistency of the same data replicas; the strategies of replication of the data and scheduling of jobs were tested by simulation. Several grid simulators were born. One of the most interesting simulators for this study is the OptorSim tool. In this chapter, the authors present an extension of the OptorSim by a consistency management module of the replicas in Data Grids; they propose a hybrid step which combines the economic models conceived for a hierarchical model with two levels. This suggested approach has two vocations, the first allowing a reduction in response times compared to an pessimistic approach, the second gives the good quality of service compared to optimistic approach.
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2 Optorsim Simulator

Resource management and scheduling of resources in large scale systems are complicated and require sophisticated tools to analyze algorithms before applying them to real systems. Many phenomena cause non-determinism of the test platform. It is customary to simulate what can iterate as necessary experience and see for example the influence of a parameter in particular on the results of simulations. As a result, many tools and standards which are specific to the application have been established. Several simulators have been proposed to study and analyze the behavior of environment types grids and management of their resources, among which, we can cite: Bricks (Takefusa, 1999), SimGrid (Casanova, 2003), GridSim (Buyya, 2002), ChicSim (Ranganathan, 2002), EdgSim (Edgsim, 2003), MicroGrid (Song, 2000), GangSim (Dumitrescu, 2005), OptorSim (Bell, 2003).

The principal motivation of OptorSim was the lack of environment of simulation for data grid treatment applications. The objective of OptorSim is to study the stability and transitory behavior of the replica optimization methods. OptorSim models the interactions of the individual data grid components design (Figure 1) drifts directly of the architecture of the data grid project. OptorSim considers the following concepts:

Figure 1.

Basic OptorSim architecture

  • The sites provide date processing and/or storage resources

  • A Broker Resource for scheduling works

  • A router is without treatment or storage resources

Work is carried out on the treatment resources and uses the data stored in the storage resources. OptorSim allows the description of the network topology by enumerating the bonds between available sites and their bandwidth.

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