Study And Implementation Of Performance Optimization SAN Cluster File System

After the analysis of the SAN environment cluster file system-SANFS(SAN cluster File System), this paper proposes and implements some technologies to improve the system's performance.Through the alteration of CIFS, SANFS utilizes the feature of SAN whose hosts can share the storage devices, it separates the stream of data and meta-data, and improves the system's I/O throughput significantly. Because of the importance of meta-data FDMT(File logical address and Disk address Map Table)and the specificity of distributed environment, the original SANFS did not deal the relationship between FDMT and OpLock(Opportunistic Locks) properly, and this caused the performance showing unstable. In order to improve the system's performance, this paper research the relationship of FDMT between the client and the MDS(Meta-Data Server) while the system is reading or writing, through redefining the time of meta data's abolition and pre-allocating and pre-fetching, the new system proposes a new lock strategy to overcome this disadvantage.This new lock strategy is managed by the MDS. Generally, it has three features as below: firstly, it separates the management of FDMT cache from the file data OpLock; secondly, it improves the utilization ratio of the FDMT cache; thirdly, because of the changing of the file accessing mode, OpLock's rule ,which implies that the request is newer, the priority is higher, is not suitable, especially when there is a writing operation, SANFS uses the new strategy to protect the FDMT used by old request and reduce the loss of the system's performance;By utilizing the feature of SAN whose hosts can access the storage device directly in the form of block device, SANFS implements soft-RAID0. By using this technology, files can be read and written on disks in parallel, and this improves the system's I/O throughput greatly.Finally, the paper tests the performance of the new and old SANFS and also the NFS. The experiments results are used to verify all of the technologies'effectiveness.