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Evaluating the Price of Consistency in Distributed File Storage Services
Résumé Distributed file storage services (DFSS) such as Dropbox, iCloud, SkyDrive, or Google Drive, offer a filesystem interface to a distributed data store. DFSS usually differ in the consistency level they provide for concurrent accesses: a client might access a cached version of a file, see the immediate results of all prior operations, or temporarily observe an inconsistent state. The selection of a consistency level has a strong impact on performance. It is the result of an inherent tradeoff between three properties: consistency, availability, and partition-tolerance. Isolating and identifying the exact impact on performance is a difficult task, because DFSS are complex designs with multiple components and dependencies. Furthermore, each system has a different range of features, its own design and implementation, and various optimizations that do not allow for a fair comparison. In this paper, we make a step towards a principled comparison of DFSS components, focusing on the evaluation of consistency mechanisms. We propose a novel modular DFSS testbed named FlexiFS, which implements a range of state-of-the-art techniques for the distribution, replication, routing, and indexing of data. Using FlexiFS, we survey six consistency levels: linearizability, sequential consistency, and eventual consistency, each operating with and without close-to-open semantics. Our evaluation shows that: (i) as expected, POSIX semantics (i.e., linearizability without close-to-open semantics) harm performance; and (ii) when close-to-open semantics is in use, linearizability delivers performance similar to sequential or eventual consistency.
   
Mots-clés
   
Citation J. Valerio, et al., "Evaluating the Price of Consistency in Distributed File Storage Services," in DAIS'13: The 13th International IFIP Conference on Distributed Applications and Interoperable Systems, Florence, Italy, 2013.
   
Type Actes de congrès (Anglais)
Nom de la conférence DAIS'13: The 13th International IFIP Conference on Distributed Applications and Interoperable Systems (Florence, Italy)
Date de la conférence 3-6-2013
Editeur commercial Springer
URL http://link.springer.com/chapter/10.1007%2F978-3-642-3854...
Liée au projet MistNet: An Experimental Peer-to-peer Platform for the Cloud