Designing a True Direct-Access File System with DevFS


Sudarsun Kannan, Andrea C. Arpaci-Dusseau, and Remzi H. Arpaci-Dusseau, University of Wisconsin—Madison; Yuangang Wang, Jun Xu, and Gopinath Palani, Huawei Technologies


We present DevFS, a direct-access file system embedded completely within a storage device. DevFS provides direct access without compromising file system integrity, concurrency, crash consistency, and security. A novel reverse-caching mechanism enables the usage of host memory for inactive objects, thus reducing memory load upon the device. Evaluation of an emulated DevFS prototype shows more than 2x higher I/O throughput with direct access and up to a 78% reduction in device RAM utilization.

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@inproceedings {210512,
author = {Sudarsun Kannan and Andrea C. Arpaci-Dusseau and Remzi H. Arpaci-Dusseau and Yuangang Wang and Jun Xu and Gopinath Palani},
title = {Designing a True Direct-Access File System with DevFS},
booktitle = {16th {USENIX} Conference on File and Storage Technologies ({FAST} 18)},
year = {2018},
isbn = {978-1-931971-42-3},
address = {Oakland, CA},
pages = {241--256},
url = {},
publisher = {{USENIX} Association},