Modular Quorum Systems Reconfigurations

Quorum systems are useful tools for implementing consistent and available storage in the presence of failures, especially in modern distributed systems such as clouds and MANETs. This paper proposes Free Store, a set of fault-tolerant protocols that emulates a register in dynamic asynchronous systems in which processes are able to join/leave the servers set by reconfigurations. The reconfiguration protocols presented are modular and loosely coupled with read/write protocols, making it easy to adapt static fault-tolerant registers to dynamic environments. By an analytical study, we show that Free Store is more efficient (in terms of communication steps) than previous solutions.