Abstract:

Destage algorithms play an important role in improving IO performance in cached RAID5 systems, In this pa- per, the authors study a number of existing  destage algorithms, and propose a destage-effieiency-first （DEF） algorithm based on the classification of system status for RAID5 systems. The main i idea of this algorithm is that destage strategy will be dynamically adjusted on the principle of detage efficiency according to the current cache occupa ncy level and varying workload. In addition, the authors present the key technology in implementing the DEF algorithm, and test and analyse the performa  nce of the algorithm.

Key words: （RAID5, small write, cache, destage）