Log Structured Filesystem Revisited: In the era of Flash Based Storage
- Title
- Log Structured Filesystem Revisited: In the era of Flash Based Storage
- Other Titles
- Log Structured Filesystem의 재조명을 위한 성능 향상기법
- Author
- 박동일
- Alternative Author(s)
- Park, Dong Il
- Advisor(s)
- 원유집
- Issue Date
- 2015-02
- Publisher
- 한양대학교
- Degree
- Master
- Abstract
- The segment based append-only update nature of the log-structured filesystem
extremely well addresses the filesystem requirement for NAND Flash storage.
Despite its promising nature, however, few users actually use the log-structured
filesystem to manage their storage in real-settings. This work provides effective
solutions to four key technical issues that existing filesystems failed to address. We
develop log-structured direct IO to support the direct IO mode of the filesystem
write operation, and suspend-aware segment cleaning to seamlessly integrate the
background segment cleaning with suspend mode of the mobile device. We find
that the most log-structured filesystems are subject to segment thrashing, while
F2FS handles fsync() efficiently. According to our extensive experiment, with
10% filesystem free space, the segment cleaning overhead becomes negligible.
We develop Disaggregate Mapping which is specifically tailored for log-structured
filesystem that not only reduces the mapping table size to 1/100 compared to page
mapping, but also manage the same lvel of write amplification. We perform comprehensive performance experiment of the developed schemes in server platform
(single SSD, RAID 0 and RAID 5) as well as smartphone (Motorolla Moto G).
The log-structured direct IO brings as much as × 6 performance improvement in
random write performance in RAID 5 against the EXT4. Suspend-aware segment
cleaning reclaims × 6 more segment than the stock segment cleaning in smartphone.
- URI
- https://repository.hanyang.ac.kr/handle/20.500.11754/128658http://hanyang.dcollection.net/common/orgView/200000425812
- Appears in Collections:
- GRADUATE SCHOOL[S](대학원) > COMPUTER SCIENCE(컴퓨터·소프트웨어학과) > Theses (Master)
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