R&D: SMRC, Endurable SSD Cache for Host-Aware Shingled Magnetic Recording Drives

IEEE Access ( Early Access ) has published an article written by Xuchao Xie, College of Computer, Liquan Xiao, College of Computer, National University of Defense Technology, Changsha 410073, China, Xiongzi Ge, Department of Computer Science, University of Minnesota-Twin Cities, Minneapolis 55455, USA, Qiong Li, College of Computer, National University of Defense Technology, Changsha 410073, China.

Click to enlarge

Abstract: “Host-Aware Shingled Magnetic Recording (HA-SMR) drives deliver higher disk capacity and expose internal zones to host, but their performance can be severely degraded when subjected to non-sequential writes (NSWs). Using Solid State Drives (SSDs) as a cache layer to proactively cache NSWs can alleviate this performance degradation. However, existing SSD caching designs are not capable of identifying and selectively caching NSWs, which incurs ineffectual SSD write traffic and excessively wears the limited write endurance of SSD. We propose SMRC, an endurable SSD caching design for HA-SMR drives. SMRC leverages the intrinsic host-aware property of HA-SMR drives to filter both sequential writes and innocuous NSWs out of SSD. Besides, SMRC reorganizes the cached NSWs to evict them with cleaning-friendly write traffic to HA-SMR drives. Our experimental results show that SMRC can effectively reduce SSD write traffic and improve system performance compared with existing SSD caching designs.“