Double parity sparing for performance improvement in disk arrays

RAID level 5 disk arrays provide highly reliable, cost effective secondary storage with high performance for reads and large writes. Small writes, however, cause the degradation of their performance, since small writes need additional disk accesses to update parity data. There have been many studies to overcome this problem. In this paper, we propose a new technique, double parity sparing, which is a variation of disk array with a spare. To improve the parity update process, the proposed scheme uses a spare block and a parity block as two available parity blocks. We present results from simulations to show that the proposed scheme offers better performance while there is no failure in disk arrays.