Disk I/O performance improvement by the file allocation, adaptive read ahead and scheduling of disks for integrated file server

Abstract

The files in integrated file server consists of dynamic files, static files and stream files. The server must satisfy not only the fast responses of both the dynamic data requests and the static data requests, but also the guaranteed bandwidth of the stream requests. This thesis introduces two kinds of researches to improve the disk I/O performance of the integrated file server. The first one, as a simulation result, deals with a block allocation method for the fast query response times of the dynamic files. The second one, as the major research topic, deals with a disk bandwidth allocation method for the stream or the static files, adaptive read ahead method of the allocated files and a disk scheduling method of the read ahead requests. The adaptive read ahead method and the file system about the file allocation method are integrated to CORE file server of our laboratory, and the disk scheduling method is in progress to be integrated. The block allocation method for the dynamic files is to maximize the concurrent disk I/O on the multiple disks. A dynamic file is represented by the Cartesian product file. Based on a quantum-inspired evolutionary computing algorithm, it distributes blocks of a binary Cartesian product file among disks. It manages the probability distribution matrix to represent the qualities of the genes. Determining the excellent genes quickly makes the method to have faster convergence than the previous work, DAGA. It gives better solutions and 3.2 - 11.3 times faster convergence than DAGA. The file allocation method is to maximize the disk I/O throughput of the static files and the stream files. The modern disk drive has multi-zones of which outer zones have higher transfer rates than the inner zones. The static file request is small and the stream file request is large. The method allocates the stream files to the outer zones with the large block sizes and the static files to the inner zones with the small block sizes. For the allocation,...