Scalable and topology-aware reconciliation on P2P networks

Abstract

International audienceCollaborative applications are characterized by high levels of data sharing. Optimistic replication has been suggested as a mechanism to enable highly concurrent access to the shared data, whilst providing full application-defined consistency guarantees. Nowadays, there are a growing number of emerging cooperative applications adequate for Peer-to-Peer (P2P) networks. However, to enable the deployment of such applications in P2P networks, it is required a mechanism to deal with their high data sharing in dynamic, scalable and available way. Previous work on optimistic replication has mainly concentrated on centralized systems. Centralized approaches are inappropriate for a P2P setting due to their limited availability and vulnerability to failures and partitions from the network. In this paper, we focus on the design of a reconciliation algorithm designed to be deployed in large scale cooperative applications, such as P2P Wiki. The main contribution of this paper is a distributed reconciliation algorithm designed for P2P networks (P2P-reconciler). Other important contributions are: a basic cost model for computing communication costs in a DHT overlay network; a strategy for computing the cost of each reconciliation step taking into account the cost model; and an algorithm that dynamically selects the best nodes for each reconciliation step. Furthermore, since P2P networks are built independently of the underlying topology, which may cause high latencies and large overheads degrading performance, we also propose a topology-aware variant of our P2P-reconciler algorithm and show the important gains on using it. Our P2P-reconciler solution enables high levels of concurrency thanks to semantic reconciliation and yields high availability, excellent scalability, with acceptable performance and limited overhead

Scientific Workflow Scheduling with Provenance Data in a Multisite Cloud

“…Compared with P2P [27,31], a major difference is that multisite cloud does not have as many sites. Another difference is that the security issue in multisite cloud is more important than in P2P, e.g.…”

Content Distribution in P2P Systems

“…Along with replication, there is the classical issue of maintaining consistency between replicas in case of content updates. In this paper, we do not discuss this issue, however good pointers can be found in our previous work [57,20].…”

Data Management in the APPA System

“…To minimize reconciliation time, such allocation should be dynamic, i.e., nodes should be allocated based on the reconciliation context (e.g., number of actions, number of replicas, network properties, etc.). We elaborated a cost model and the associated algorithms for allocating reconciler nodes based on communication costs [25,26]. These algorithms take into account cost changes due to dynamic disconnections and reconnections.…”