Z-LFS: A Zoned Namespace-tailored Log-structured File System for Commodity Small-zone ZNS SSDs

This paper presents a novel zoned namespace (ZNS) tailored log-structured file system (LFS) called Z-LFS for commodity small-zone ZNS SSDs. Specifically, Z-LFS first enables append-only updates on metadata while leveraging the unique metadata characteristic of LFS on ZNS SSDs. Second, Z-LFS devises speculative log stream management according to the workload temperature to maximize active zone utilization. Finally, Z-LFS adopts conflict-aware zone allocation to minimize resource contention within ZNS SSDs while considering LFS features. We implement Z-LFS based on F2FS in the Linux kernel and evaluate it with commodity ZNS SSD. Our evaluations show that Z-LFS achieves higher performance by up to 33.44× and 3.5× compared with F2FS and a state-ofthe-art interface for commodity ZNS SSDs, respectively.