Prologue - What is Large-scale Processing?

Published: March 18, 2026 3 AM, October 2025. A single DNS configuration error on an AWS server brought Snapchat, Roblox, and McDonald's to a standstill. 3,500 companies across 60 countries were stopped cold by one small crack. Systems are far more fragile than we think. Large-scale processing isn't a trend about boosting server specs. It's the engineering discipline that keeps services alive at the edge of their limits. So where does "large-scale" actually begin? 10,000 users? A million? That's