Minimizing the Buffer Size in Fault-Tolerant Video Servers for VBR Streams

摘要

To guarantee the high reliability of video services, video servers usually adopt parity-encoding techniques in which data blocks and their associated parity blocks form a parity group. For real-time video service, all the blocks in a parity group are prefetched in order to cope with a possible disk failure, thereby incurring a buffering overhead. In this paper, we propose a new scheme called Round-level Parity Grouping (RPG) to reduce the buffer overhead while restoring VBR video streams in the presence of a faulty disk. RPG allows variable parity group sizes so that the exact amount of data is retrieved during each round. Based on RPG, we have developed a storage allocation algorithm for effective buffer management. Experimental results show that our proposed scheme reduces the buffer requirement by 20% to 25%.