“Lift and Shift” (or cloud lift) is often sold as the path of least resistance for migrating legacy systems to the cloud. The theory is simple: take your on-premises virtual machines (VMs), copy them to an IaaS provider like Azure, and enjoy immediate scalability.

However, when dealing with large-scale, mission-critical systems, the physics of the cloud are different from an on-premises data center. Assumptions made about network adjacency and connection limits can lead to catastrophic performance failures that only appear during full-load testing.