Highly Scalable Distributed Architecture for NoSQL Datastore Supporting Strong Consistency

Introducing a strong consistency model into NoSQL data storages is one of the most interesting issues nowadays. In spite of the CAP theorem, many NoSQL systems try to strengthen the consistency to their limits to better serve the business needs. However, many consistency-related problems that occur in popular data storages are impossible to overcome and enforce rebuilding the whole system from scratch. Additionally, providing scalability to those systems really complicates the matter. In this paper, a novel data storage architecture that supports strong consistency without loosing scalability is proposed. It provides strong consistency according to the following requirements: high scalability, high availability, and high throughput. The proposed solution is based on the Scalable Distributed Two-Layer Data Store which has proven to be a very efficient NoSQL system. The proposed architecture takes into account the concurrent execution of operations and unfinished operations. The theoretical correctness of the architecture as well as experimental evaluation in comparison to traditional mechanisms like locking and versioning is also shown. Comparative analysis with popular NoSQL systems like MongoDB and MemCached is also presented. Obtained results show that the proposed architecture presents a very high performance in comparison to existing NoSQL systems.