SmartNetSSD: Exploiting Path Resources for Read Performance Improvement in Network-Based SSDs

With the bit density improvement and the three-dimensional NAND flash techniques, solid-state drives (SSDs) dramatically increase the storage capacity and performance. However, the incorporation of multiple flash chips within a single flash channel structure in SSDs introduces the access path conflicts when servicing multiple I/O requests accessing flash chips on the same channel. To meet the increasing performance demands of modern applications, network SSDs that employ the interconnection network of flash chips, has a high potential to address the access path conflicts by fundamentally increasing the number of the available access paths. In this paper, we propose SmartNetSSD, a new scheme that utilizes the path diversity in network SSD to dramatically mitigate access path conflicts. SmartNetSSD employs the following key techniques: 1) A multi-path routing algorithm, MProuting, identifies the multiple access paths for read operations. 2) A network-based read-retry technique, NetRR, pipelines the con-secutive read-retry steps for a read operation across the multiple access paths. The experimental results show that SmartNetSSD improves I/O performance by an average of 46.29% over the state-of-the-art approach.