SMRTS: A Performance and Cost-Effectiveness Optimized SSD-SMR Tiered File System with Data Deduplication

Storage tiering (e.g., SSD+HDD) is designed to achieve a better tradeoff between performance and cost-effectiveness for storage systems. With the development of Shingled Magnetic Recording (SMR) drives, replacing conventional HDD with a higher density of SMR drives in tiered storage can further improve cost-effectiveness. However, with data tracks overlapped in SMR drives, the "non-sequential' writes in SMR drives cause explicit performance penalties, which is the most challenging issue of using SMR drives in storage tiering.In this paper, we present SMRTS, a file system for SSD-SMR tiered storage with data deduplication. First, SMRTS deduplicates the files being migrated from SSD to SMR to solve the non-sequential write issue of SMR drives and further optimize the space utilization. Second, to address the performance overhead caused by deduplication, we propose file recipe reuse and refresh, hints-based container allocations, and fast container validation to address the penalties caused by data fragmentations. We conduct experimental evaluations of SMRTS using both benchmarks and real-world workloads. The evaluation results show that compared with a compatible file system on SSD+HDD tiered storage, SMRTS achieves a similar performance but provides a much larger space (at least 1.25X). The proposed optimizations improve migration performance up to 17X.