Programming Partition-Aware Network Applications

We consider the problem of developing reliable applications to be deployed in partitionable asynchronous distributed systems. What makes this task difficult is guaranteeing the consistency of shared state despite asynchrony, failures and recoveries, including the formation and merging of partitions. While view synchrony within process groups is a powerful paradigm that can significantly simplify reasoning about asynchrony and failures, it is insufficient for coping with recoveries and merging of partitions after repairs. We first give an abstract characterization for shared state management in partitionable asynchronous distributed systems and then show how views can be enriched to convey structural and historical information relevant to the group's activity. The resulting paradigm, called enriched view synchrony, can be implemented efficiently and leads to a simple programming methodology for solving shared state management in the presence of partitions.