This white paper discusses the concept of shared data scale-out clusters, as well as how they deliver continuous availability and why they are important for delivering scalable transaction processing support. It also contrasts this approach, taken in a relational database context, with clustering approaches employed by NoSQL databases and Hadoop applications, showing the importance It goes on to discuss the specific advantages offered by IBM’s DB2 pureScale, which is designed to deliver the power of server scale-out architecture, enabling enterprises to affordably develop and manage transactional databases that can meet the requirements of a cloud-based world with rapid transaction data growth, in an affordable manner.