A Fully Distributed Quorum Consensus Method with High Fault-Tolerance and Low Communication Overhead

The main objective of data replication in a distributed database system is to provide high data availability for transaction processing. Quorum consensus (QC) methods are commonly applied to managing replicated data. In this paper, we present a new QC method. The proposed QC method is highly fault-tolerant, and fully distributed (i.e., each site in a distributed system is equally weighted). Further, we can show that the proposed QC method has a low message overhead: 1. (1) In the best case, each transaction operation process needs only to communicate with Ω(√n) remote sites to get permission (n is the number of sites storing replicated copies of the manipulating data item). 2. (2) In the worst case, each transaction operation process may be forced to communicate with Ω(√n log n) remote sites due to site failures. We also compare our method with the existing QC methods.