Contributing Storage Using the Transparent File System
James Cipar, Mark D. Corner, and Emery D. Berger - University of Massachusetts Amherst
- James Cipar, Mark D. Corner, and Emery D. Berger. Contributing Storage Using the Transparent File System. ACM Transactions on Storage, 3(3), 2007.
Contributory applications allow users to donate unused resources on their personal computers to
a shared pool. Applications such as SETI@home
, and Freenet are now in wide use
and provide a variety of services, including data processing and content distribution. However,
while several research projects have proposed contributory applications that support peer-to-peer
storage systems, their adoption has been comparatively limited. We believe that a key barrier to
the adoption of contributory storage systems is that contributing a large quantity of local storage
interferes with the principal user of the machine.
To overcome this barrier, we introduce the Transparent File System (TFS). TFS provides background
tasks with large amounts of unreliable storage - all of the currently available space -
without impacting the performance of ordinary file access operations. We show that TFS allows
a peer-to-peer contributory storage system to provide 40% more storage at twice the performance
when compared to a user-space storage mechanism. We analyze the impact of TFS on replication
in peer-to-peer storage systems and show that TFS does not appreciably increase the resources
needed for file replication.
The authors create a cooperative file system by implementing a transparent block allocation structure.
Transparent blocks may be overwritten at any time by the local user. Thus TFS is an unreliable but
easy to deploy system upon which higher level storage abstractions may be built.
- 28 Nov 2007