IMPROVING PERFORMANCE OF THE DISTRIBUTED FILE SYSTEM USING SPECULATIVE READ ALGORITHM AND SUPPORT-BASED REPLACEMENT TECHNIQUE

Cloud computing systems use distributed file systems (DFSs) to store and process large data generated in the organizations. The users of the web-based information systems very frequently perform read operations and infrequently carry out write operations on the data stored in the DFS. Various caching and prefetching techniques are proposed in the literature to improve performance of the read operations carried out on the DFS. In this paper, we have proposed a novel speculative read algorithm for improving performance of the read operations carried out on the DFS by considering the presence of client-side and global caches in the DFS environment. The proposed algorithm performs speculative executions by reading the data from the local client-side cache, local collaborative cache, from global cache and global collaborative cache. One of the speculative executions will be selected based on the time stamp verification process. The proposed algorithm reduces the write/update overhead and hence performs better than that of the non-speculative algorithm proposed for the similar DFS environment.