Based On P2p Distributed Storage

Research & Implementation of distributed storage system based on P2P model is a project supported by "Youth Software Creative Engineering" from Technological Office of SiChuan.The system is designed as a Server-to-Server model based on peer-to-peer technology. All servers are peer to peer, and linked with route. Any client can query and access every file of the system from any node. And any file of each node is backup to some other servers with its storage information automatically to improve the fault-tolerant ability of the whole system. Moreover, file storage information is described in XML language, which benefits the access and issue process of the file information through web.In this thesis, the general I/O models are introduced first, then some typical internal architectures for network server, and basic concept, semantic rules of XML language are discussed sequentially. Then, we compared all kinds of search algorithm for P2P resources, and described the design principle of a keyword based routing model that runs on our system in detail. Depending on our research on the distributed storage technology as below, we finally designed and implemented a P2P based distributed storage system. This layered system includes an underlying router layer, an upper object transfer layer and a command dispatch layer which implements a thread-pool-based and task driven architecture, and is listening on an UDP port. A global task queue is maintained in the command dispatch layer and used to dispatch and transfer each command to the object transfer layer. In the object transfer layer, we implemented a resource search algorithm, an UDP based transfer protocol for the interaction between a client and a server or two servers. At last, a timer module is developed, in order to implement a asynchronous response for those high delayed tasks through a scheduled task queue, and make it possible for those tasks to re-send package under expiration situation.Finally, we proved that the initial goal is reached and a good performance is achieved by taking the system in some functionality tests.