Boosting up the Mount Latency of NAND Flash File System using Byte-addressable NVRAM
Byeong-Gil Jeon, Eun-Ki Kim, Hyungjong Shin, Seok-Hee Han, Yoo-Jip Won · 2008
This paper describes an improvement of mount-time delay in NAND Flash file systems. To improve file system mount performance, this work configures a hierarchical storage system with byte-addressable NVRAM and NAND Flash memory, and let the meta data of a file system allocated in the NVRAM. Since the meta data are stored in NVRAM supporting data integrity some of the items, which are stored in Spare area and Object Header area of NAND Flash memory to control meta data of NAND Flash file system, could be eliminated. And also, this work eliminates the scanning operation of the Object Header area of previous work FRASH1.0. The scanning operation is definitely required to find out the empty Object Header address for storing the Object Header data and provokes a certain amount of performance loss in file generation and deletion. In this work, an implemented file system, so-called FRASH1.5, is demonstrated, featuring new data structures and new algorithms. The mount time of FRASH1.5 becomes twice as fast as that of the FRASH1.0. The performance in file generation gets improved by about . In particular, for most large-size files, the FRASH1.5 has 8 times faster mount time than YAFFS, without any performance loss as seen in the file generation.