HIFFS: A Hybrid Index for Flash File System

Flash memory, especially NAND flash memory, has become a popular alternative for the design of storage system. Index schemes of conventional file systems do not take the flash memory characteristics into account and will cause poor performance. The current flash file systems work well only in the case of small capacity. To address the problem, we propose a new hybrid indexing scheme both in directory structure and file data index for NAND flash file system in this paper, which is called HIFFS (a Hybrid Index for Flash File System). HIFFS contains two components: hash tree directory and adaptive file data index. The hash tree directory uses a hash-based index to get better update performance and search efficiency. The adaptive file data index uses different file index strategy according to file size. The experiment results show that HIFFS outperforms the state-of-the-art file systems both in throughput.