Impact of stripe unit size on performance and endurance of SSD-based RAID arrays

Over the past decades, redundant array of independent disks (raids) havebeen congured based on mechanical characteristics of hard disk drives (hdds). withthe advent of solid-state drives (ssds), congurations such as stripe unit size can be farfrom the characteristics of ssds. in this paper, we investigate the eect of stripe unitsize on the endurance and the overall i/o performance of an ssd-based raid array andcompare the optimal stripe unit size with the suggested stripe unit sizes for hdd-basedraid. to this end, we rst examine the number of extra page reads and writes imposedby write requests, and then observe the corresponding impact on the overall throughputand the average response time of ssd-based raid arrays. the eect of extra page writesfor dierent stripe unit sizes and their impact on endurance has been also examined. tovalidate the analytical study, we have used i/o intensive traces and simulated an ssd-basedraid array, using disksim simulator with dierent stripe unit sizes. the experimentalresults reveal that unlike hdd-based raid arrays, a 4 kb stripe unit size can signicantlyimprove the throughput, response time and endurance of an ssd-based raid4 array (upto 67.6%, 52.2%, and 48.6%, respectively), as compared to 128 kb stripe unit size.