Title
Optimizing File Systems with a Write-Efficient Journaling Scheme on Non-Volatile Memory
Abstract
Modern file systems employ journaling techniques to guarantee data consistency in case of unexpected system crashes or power failures. However, journaling file systems usually suffer from performance decrease due to the extra journal writes. Moreover, the emerging non-volatile memory technologies (NVMs) have the potential capability to reduce the journaling overhead by being deployed as the journaling storage devices. However, traditional journaling techniques, which are designed for hard disks, fail to perform efficiently in NVMs. In order to address this problem, we propose an NVM-based journaling scheme, called NJS. The basic idea behind NJS is to reduce the journaling overhead of traditional file systems while fully exploiting the byte-accessibility characteristic of NVM, and alleviating the slow write and endurance limitation of NVM. Our NJS consists of four major contributions: (1) In order to decrease the amount of journal writes, NJS only needs to write the file system metadata and over-write data to NVM as write-ahead logging, thus alleviating the slow write and endurance limitation of NVM. (2) NJS adopts a wear aware strategy for NVM journal block allocation in which each block can be evenly worn out, thus further extending the lifetime of NVM. (3) We propose a novel journaling update scheme in which journal data blocks can be updated in the byte-granularity based on the difference of the old and new versions of journal blocks, thus fully exploiting the unique byte-accessibility characteristic of NVM. (4) NJS includes a garbage collection mechanism that absorbs the redundant journal updates, and actively delays the checkpointing to the file system. Evaluation results show the efficiency and efficacy of NJS. For example, compared with Ext4 with a ramdisk-based journaling device, the throughput improvement of Ext4 with our NJS is up to 131.4 percent.
Year
DOI
Venue
2019
10.1109/TC.2018.2870380
IEEE Transactions on Computers
Keywords
Field
DocType
Nonvolatile memory,Metadata,Throughput,Random access memory,System performance,Phase change materials,Computer crashes
Metadata,File system,Computer science,ext4,Parallel computing,Journaling file system,Non-volatile memory,Garbage collection,Throughput,Operating system,Data consistency
Journal
Volume
Issue
ISSN
68
3
0018-9340
Citations 
PageRank 
References 
1
0.35
0
Authors
4
Name
Order
Citations
PageRank
Xiaoyi Zhang1698.76
Dan Feng21845188.16
Yu Hua357854.94
Jianxi Chen415310.60