Dynamic Management of Highly Replicated Data

We present an efficient replication control protocol for managing replicated data objects that have more than five replicas. Like the grid protocol, our dynamic group protocol requires only O(Ö# # n ) messages per access to enforce mutual consistency among n replicas. Unlike other protocols aimed at providing fast access, our protocol adapts itself to changes in site availability and network connectivity, which allows it to tolerate n - 2 successive replica failures. We evaluate under standard Markovian assumptions the availability of a replicated object consisting of n replicas managed by our dynamic group protocol when the n replicas are on the same LAN segment and find it to equal that of an object with the same number of replicas managed by the dynamic-linear voting protocol. Keywords: distributed consensus, replicated data, replication control, voting, network partitions. 1. Introduction Many large-scale distributed systems have data that are replicated at a large number of sit..