Multi-agent based file replication and consistency

Replication is a well-known technique in distributed systems. Replication can reduce data access latency, enhance and optimize the availability and reliability of the entire system. The existence of multiple instances of data however causes additional issues. The main issue is consistency of data. In this paper we present a multi-agent based approach for file replication and consistency management. We describe the design of a multi-agent system using JADE platform. The system presents a multi-agent based communication framework that enables the replication and maintenance of files. In this study, JADE is used to implement the multi-agent system. Jade is a middleware that facilitates the development of multi-agent systems. It is FIPA compliant, an organization that defines the standards for multi-agent systems. Jade provides tools and libraries to create and manage agents which communicate with each other. JADE also supports graphical user interfaces that can be used for debugging, monitoring, logging and management of the agent system. Presented system consists of two separated application, named Front-End and Back-End. Front-End provides a Java Swing Bases interface to clients with common file management functionalities. Create, modify, display or token demands of files are managed by proposed GUI. Presented GUI communicates with a JADE agent to establish relation with Back-End. Back-End contains multiple agent containers, with each agent container representing a storage service. The system supports both synchronous and asynchronous replication. On synchronous mode, all modifications are propagated simultaneously to all agent containers. On asynchronous mode, only the current agent container storage is affected of modifications. Presented mobile agents notifies other agent containers about the modifications. Propagation only occurs when a pull request is made by other agent container. File modifications require token of the mentioned file to access the system. Client must get the token first to send file modification request. Every file stored in the system is assigned with a single token between all agent containers. The period of validity of tokens are defined by a given time of system admin.