Dynamic-size Superblock Management based on Buddy System for Modern SSDs

Superblocks are widely used in SSDs to exploit internal parallelism thus improving I/O throughput. Although dynamic-size superblock schemes enhance space utilization for varied workloads, they introduce internal fragmentation and impact overall performance. To address this issue, we propose Buddy , a novel dynamic-size superblock management scheme based on the buddy system, which adapts to I/O patterns by dynamically splitting and merging superblocks. This approach maintains large blocks to preserve parallelism for sequential writes and generates smaller blocks on demand to handle random writes effectively. We further introduce the expansion GC mechanism to adaptively adjust GC unit size based on I/O intensity and GC efficiency for alleviating fragmentation and preserving SSD parallelism. Trace-driven evaluations with real-world benchmarks demonstrate that our approach can reduce average I/O latency and GC-induced data migration by 47.0 % and 24.5 %, respectively, compared to state-of-the-art superblock management techniques.