Dual-Stack Migrations: How to Move Petabytes Without Losing Sleep

Real-world archive migrations aren’t about a single cutover—they require 2–2.5 years of dual-stack overlap. Run old and new systems in parallel, track metrics on separate telemetry stacks, maintain independent alert planes, budget 25–40% extra capacity, plan for peak power/cooling, and rehearse rollback drills. The goal: 90 days of stable ingest, verified parity, and zero P1 incidents.