Moving large-scale financial systems to the public cloud is a high-stakes game. In regulated industries, you often cannot perform casual test-in-production experiments. You have to design correctly and then verify quickly.

When migrating a massive data warehouse (DWH) from on-premises hardware to AWS EC2, the natural instinct is to match specifications: “If I had 16 cores and 128 GB RAM on-prem, I need an x1e.xlarge on AWS.”