Cloud-based file synchronization services, such as Dropbox and OneDrive, are a worldwide resource for many millions of users. However, individual services often have tight resource limits, varying performance in regions of the world, temporary outages or even shutdowns, and sometimes silently corrupt or leak user data.

We design, implement, and evaluate MetaSync, a secure and reliable file synchronization service that uses multiple cloud synchronization services as untrusted storage providers. To make MetaSync work correctly, we devise a novel variant of Paxos that provides linearizable updates on top of the unmodified APIs exported by existing services. Our system automatically redistributes files upon adding, removing, or resizing a provider with a novel deterministic replication scheme.

Our evaluation shows MetaSync provides low update latency and high update throughput, close to the performance of commercial services, but is more reliable and available. For synchronization, MetaSync outperforms its underlying cloud services by 1.2X-10X on three realistic workloads.

This is joint work with Haichen Shen (UW), Taesoo Kim (GaTech), Arvind Krishnamurthy (UW), Thomas Anderson (UW), and David Wetherall (UW).

Seungyeop Han is a Ph.D student in the Department of Computer Science and Engineering at University of Washington. His research interests are in the broad area of distributed systems and computer networks, and also include related topics like security and privacy. He has published papers in the premier conferences such as SIGCOMM, Ubicomp, NSDI, CCS, Usenix Security, NIPS, and WWW.

He received KFAS fellowship in computer science (2010-). Prior to studying in UW, he worked for Naver as a software engineer for 3 years. He received his B.S. (2005) and M.S. (2007) in Computer Science from KAIST.