USFS: Harnessing Used Disk Space

• Overview of USFS
• Papers
• Funding
• People

Overview of USFS

USFS is a peer-to-peer (p2p) enhancement for the widely-used Network File System (NFS). USFS harvests redundant storage space on cluster nodes and user desktops to provide a reliable, shared file system that acts as a large storage with normal NFS semantics. P2p storage systems provide location transparency, mobility transparency, load balancing, and file replication -- features that are not available in NFS. On the other hand, NFS provides hierarchical file organization, directory listings, and file permissions, which are missing from p2p storage systems. By blending the strengths of NFS and p2p storage systems, USFS provides a low overhead storage solution.

We have developed a prototype USFS on both FreeBSD and Linux. Our experiments show that compared to unmodified NFS, USFS introduces a 4.1% fixed overhead and 1.5% additional overhead as nodes are increased from one to eight. For larger number of nodes, the additional overhead increases slowly. USFS achieves load balancing in distributed directories, and guarantees 99.99% or better file availability.

Papers

• Kosha: A Peer-to-Peer Enhancement for the Network File System.
  Ali R. Butt, Troy A. Johnson, Yili Zheng, Y. Charlie Hu.
  In Journal of Grid Computing, Special Issue on Peer-to-Peer and Grid Computing, Volume 4 (3), pp. 323-341, September 2006. (acceptance rate: 25%)
  PDF
• Kosha: A Peer-to-Peer Enhancement for the Network File System.
  Ali R. Butt, Troy A. Johnson, Yili Zheng, Y. Charlie Hu.
  In Proceedings of IEEE/ACM SC'2004, Pittsburgh, PA, November 6-12, 2004. (59/192 30%)
  PDF

Funding

People

• Faculty: Y. Charlie Hu
• Students: Zheng Zhang
• Former members: Ali R. Butt, Troy Johnson, Yili Zheng