They sure are one of the FASTEST! Congratulations to the BetrFS team, with FAST acceptances two years in a row!

Optimizing Every Operation in a Write-Optimized File System
<a href="http://www.cs.stonybrook.edu/~junyuan/">Jun Yuan, <a href="http://www.cs.stonybrook.edu/~yazhan/">Yang Zhan, <a href="http://www.cs.stonybrook.edu/~wjannen/">William Jannen, <a href="http://www.cs.stonybrook.edu/~ppandey/">Prashant Pandey, <a href="http://www.cs.stonybrook.edu/~aakshintala/">Amogh Akshintala, <a href="http://www.cs.stonybrook.edu/~kchandnani/">Kanchan Chandnani, <a href="https://sites.google.com/site/poojadeo1991/">Pooja Deo, Zardosht Kasheff, Leif Walsh, <a href="http://www.cs.stonybrook.edu/~bender/">Michael Bender, <a href="http://www.cs.rutgers.edu/~farach/">Martin Farach-Colton, <a href="http://www.cs.stonybrook.edu/~rob/">Rob Johnson, <a href="http://people.csail.mit.edu/bradley/">Bradley C. Kuszmaul, and <a href="http://www.cs.stonybrook.edu/~porter">Donald E. Porter
In the Proceedings of the 14th USENIX Conference on File and Storage Technologies (<a href="https://www.usenix.org/conference/fast16">FAST ‘16), Santa Clara, CA, February 2016.