Section: Software

SwiftCloud

Participants : Marc Shapiro [correspondent] , Marek Zawirski, Annette Bieniusa, Valter Balegas.

SwiftCloud is a platform for deploying large-scale distributed applications on the edge, close to the users. Internet delays are a problem for interactive distributed applications. Truly optimal responsiveness and availability require mutable shared state replicated near the client, at the network edge. This raises serious challenges of consistency, fault tolerance, and programmability. The SwiftCloud system is designed to address these challenges. Our data model is based on client-side caching of shared mutable objects, made practical with a library of synchronisation-free, yet provably correct object types (CRDTs). The consistency model combines eventual consistency, absence of roll-backs, transactional consistency and session guarantees, but stops short of serialisability. This programming model is practically useful, yet does not require synchronisation, thus ensuring scalability. Maintaining the guarantees at a reasonable cost is especially challenging at large scale. Scalability and programmability are helped by several design decisions detailed in the paper. We validated our approach by building the SwiftCloud platform, by deploying three significant applications, and by measuring their performance in different configurations, in order to explore the benefits of replication at different locations.

SwiftCloud was supported by the ConcoRDanT ANR project (Section  8.1.4 ) and a Google European Doctoral Fellowship (Section  8.2.2.1 ).

The code is freely available on http://gforge.inria.fr/ under a BSD license.