Tree-Based Consistency Approach for Cloud Databases

Database as a Service is a very attractive product from cloud service providers for small start-up companies. However, consistency maintenance among replica servers is a very big issue in cloud databases. Too much interdependency of replica servers in the existing consistency model reduces performance and throughput, and can increase the transaction failure rate of a cloud database. In this paper we propose a tree-based consistency approach that reduces interdependency among replica servers by introducing partially consistent and fully consistent states of cloud databases. The tree is formed such a way that the maximum reliable path is ensured from the primary server to all replica servers. As a result, the probability of a transaction failure is greatly reduced, which helps to increase performance and throughput even in an unreliable network.