Barrier-Enabled IO Stack for Flash Storage


Youjip Won, Hanyang University; Jaemin Jung, Texas A&M University; Gyeongyeol Choi, Joontaek Oh, and Seongbae Son, Hanyang University; Jooyoung Hwang and Sangyeun Cho, Samsung Electronics
Awarded Best Paper!


This work is dedicated to eliminating the overhead required for guaranteeing the storage order in the modern IO stack. The existing block device adopts a prohibitively expensive approach in ensuring the storage order among write requests: interleaving the write requests with Transfer-and-Flush. Exploiting the cache barrier command for Flash storage, we overhaul the IO scheduler, the dispatch module, and the filesystem so that these layers are orchestrated to preserve the ordering condition imposed by the application with which the associated data blocks are made durable. The key ingredients of Barrier-Enabled IO stack are Epoch-based IO scheduling, Order-Preserving Dispatch, and Dual-Mode Journaling. Barrier-enabled IO stack can control the storage order without Transfer-and-Flush overhead. We implement the barrier-enabled IO stack in server as well as in mobile platforms. SQLite performance increases by 270% and 75%, in server and in smartphone, respectively. In a server storage, BarrierFS brings as much as by 43$\times$ and by 73$\times$ performance gain in MySQL and SQLite, respectively, against EXT4 via relaxing the durability of a transaction.

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@inproceedings {210532,
author = {Youjip Won and Jaemin Jung and Gyeongyeol Choi and Joontaek Oh and Seongbae Son and Jooyoung Hwang and Sangyeun Cho},
title = {{Barrier-Enabled} {IO} Stack for Flash Storage},
booktitle = {16th USENIX Conference on File and Storage Technologies (FAST 18)},
year = {2018},
isbn = {978-1-931971-42-3},
address = {Oakland, CA},
pages = {211--226},
url = {},
publisher = {USENIX Association},
month = feb