A dynamic parity grouping for efficient parity buffering for RAID-5 disk arrays

摘要

One major drawback of a RAID-5 disk array system is that an update to a data block may involve four disk accesses, including reading the old data, writing the new data, reading the old parity and writing the new parity. Such a high overhead is especially undesirable for workloads with high update rates. One approach to alleviating this problem is to buffer parity blocks in the disk controller cache. In this paper, we present a dynamic parity grouping (DPG) scheme for efficient parity buffering for a RAID-5 system.