ConZone+: Practical Zoned Flash Storage Emulation for Consumer Devices

Consumer flash storage uses block interfaces, leading to performance and endurance issues like large mapping table overhead and write amplification. While zoned abstraction solves these problems in enterprise devices, it introduces new challenges for consumer devices with limited volatile memory and suboptimal file system design. These challenges highlight the need for a better understanding and new designs for zoned storage in consumer devices. We propose ConZone+, a practical and accurate emulation framework designed for consumer-grade zoned flash storage. Unlike existing enterprise-focused emulators, ConZone+  models unique consumer constraints (e.g., limited mapping caches and write buffers, hybrid flash media) and hybrid mapping. Furthermore, to enable system-level emulation, ConZone+  supports block interface for metadata area in file system and provides several useful scripts to assist users. Finally, ConZone+  introduces several enhancements on the firmware logic, including a configurable per-chip command queue, variable zone sizes, and compatibility with non-power-of-two block sizes. Users can explore the internal architecture and management strategies of consumer-grade zoned flash storage and integrate their optimizations into system software with ConZone+. To evaluate the accuracy of ConZone+, we configure it referencing a mobile phone equipped with zoned flash storage and compare its performance to that. The evaluation results show that the average performance deviations are limited to 12.8% for writes and 10% for reads. In addition, we conduct several case studies using ConZone+ to explore the firmware design and the adaptability of the log-structured features of F2FS and the transaction processing of SQLite.