EC-ARR: Using Active Reconstruction to Optimize SSD Read Performance

Solid State Drive (SSD) has been becoming mainstream storage for its high performance, affordability proportional to its growing storage capacity. However, some inborn characteristics still limit its widespread application: (1) It wears out easily with increasing times of being written/erased. Therefore, SSDs are generally equipped with dedicated Erasure Coding (EC) modules for reliability concerns. However, the EC modules are only statically useful in the sheer scenarios of data loss. In other words, the EC module is never exploited in the regular access situations of dominating frequency, where data is unharmed and intact. (2) Huge latency differences exist among its three basic operations of reading, writing, and erasing, which could lead to performance degradation if there is no proper I/O scheduling. (3) SSD has excellent internal parallelism, which offers a strong possibility to further boost I/O performance if exploited properly.