ZZFS: A Hybrid Device and Cloud File System For Spontaneous Users

Michelle L. Mazurek, Eno Thereska, Dinan Gunawardena, Richard Harper, James Scott

Proceedings of the 10th Usenix Conference on File and Storage Technologies (FAST'12) |

Published by USENIX

Good execution of data placement, caching and consistency policies across a user’s personal devices has always been hard. Unpredictable networks, capricious user behavior with leaving devices on or off and non-uniform energy-saving policies constantly interfere with the good intentions of a storage system’s policies. This paper’s contribution is to better manage these inherent uncertainties. We do so primarily by building a low-power communication channel that is available even when a device is off. This channel is mainly made possible by a novel network interface card that is carefully placed under the control of storage system protocols. The design space can benefit existing placement policies (e.g., Cimbiosys [21], Perspective [23], Anzere [22]). It also allows for interesting new ones. We build a file system called ZZFS around a particular set of policies motivated by user studies. Its policies cater to users who interact with the file system in an ad hoc way — spontaneously and without pre-planning.