eljefe6a writes: "Putting some numbers and data behind the Hadoop hype took a few months of research. I ran 1, 2, 3, 4, 5, 10 and 20 node Hadoop clusters using Elastic MapReduce to check its scalability. As expected, Hadoop scales very well. I also run performance tests on EC2 instances. Then, I break down the ROI of Spot Instance market and cost per unit."