Testing Cloud Benchmark Scalability with Cassandra

NoSQL databases were developed as highly scalable databases that allow easy data distribution over a number of servers. With the increased interest of researchers and companies in non-relational technology, NoSQL databases became widely used and a common belief emerged defending that those engines scale well. This means that the use of more nodes would result in reduced execution time of requests and the system would scale adequately, by adding nodes proportionally to data size and load. However, sometimes, adding nodes may not result in improvement of request-serving time. Therefore, it is useful to investigate how different factors, such as workload, data size and number of simultaneous sessions influence scaling capabilities. We will review the architecture of Cassandra, which is known for being one of the most efficient NoSQL engines, and analyze its scalability, using the Yahoo Cloud Serving Benchmark. The results will allow a better understanding of scalability and scalability limitations in that type of environment.