Abstract: In big data era, various applications bring increasingly higher demands on storage system' capacity, performance and reliability. New storage media brings good opportunity in improving the performance of storage system, and Redundant Array of Independent SSDs (RAIS) has been widely used in various storage systems. Data reconstruction, however, takes long time and affects its ability of provid- ing I/O access services to upper level applications, when a disk fails in RAIS. A storage pool architecture supporting multithreading and concurrent processing is designed and implemented, in which I/O requests evenly distributed in all SSDs can be processed concurrently and the access performance of user I/O and data reconstruction I/O are improved. A workload-adaptive I/O scheduling strategy is proposed, which can guarantee the quality of user I/O service and improve the efficiency of data reconstruction. Experimental results show that the multithreaded concurrent I/O processing architecture based on storage pool can improve data reconstruction performance. The workload-adaptive I/O scheduling strategy can adjust the scheduling ratio of user I/O and data reconstruction I/O dynamically, ensure the service quality of user I/O and improve the efficiency of data reconstruction. 

Key words: flash array, RAIS technology, data protection, storage pool, data reconstruction