Performance Evaluation of Multi-Head Logging in Flash File Systems

As NAND flash memory has become a widely used storage medium, traditional file systems face challenges in adapting to its unique characteristics. The Flash-Friendly File System (F2FS) is designed to optimize file and data management on NAND flash, addressing issues such as raw NAND interface compatibility, the "wandering tree" problem, high reading costs, and inefficient garbage collection. Through a log-structured foundation and various optimizations, including multi-head logging, node address table (NAT), and reserved in-place updated metadata sections, F2FS achieves enhanced performance, reliability, and prolonged lifespan. This study constructs a multi-head log model based on F2FS and introduces a new hardware-independent metric—Write Amplification Factor (WAF)—to analyze performance. The research demonstrates that separating node and data blocks is more effective in improving garbage collection efficiency than simple hot and cold data segregation.