Journaling of Journal

Journaling of Journal Is (Almost) Free on FAST 2014.

Journaling is the technology to protect data consistency and durability despite sudden system crashes. However, while a robust journaling file system can protect the corruption of the file system itself, it can not protect the user’s data. As a results, many applications use rollback-recovery journaling to record REDO or UNDO information in a log file. This journaling (file system journal) of journal performs unnecessary write, thus cause performance penalty.

Because the log file of applications is a safe journal, this paper propose selectively reduce the file system journal operations. Single-I/O use buffer to merge multiple application I/Os into a single commit. File-Adaptive Journaling selectively provide file level option of journal preference, such as ordered journaling and full data/metadata journaling.

Additional Read: Consistency Cost in NVM-based Single Level Systems.