Virtual Striping: A Storage Management Scheme with Dynamic Striping (Special Issue on Architectures, Algorithms and Networks for Massively parallel Computing)

概要

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RAID5 disk arrays provide high performance and high reliability for reasonable cost. However RAID5 suffers a performance penalty during block updates. In this paper, we propose a method to improve the small write performance of RAID5 disk arrays, named Virtual Striping. Instead of updating each block independently, this method buffers a number of updates, generates a new stripe composed of the newly updated blocks, then writes the full stripe back to disk. In order to make free space for write operations, new garbage collection strategy is employed, where the linkage of blocks in a parity stripe is changed in Virtual Striping. The LFS (log-structured file system) based storage management scheme also writes new block onto large free area, which uses copying garbage collection. In this paper, we compare the performance of both methods through simulation. Although the write cost of Virtual Striping is more than that of the LFS based method, Virtual Striping has better performance than the LFS based method. This is due to the high efficiency of garbage collection in Virtual Striping.
1996-08-25