Nothing Fails Alone
Evidence from one quarter
Every DR plan rests on two assumptions nobody tests: that zones fail independently, and that the control plane answers when you need it. 2026 tested both.
4 parts
AZ Isolation Held. Your Architecture Didn't.
A cooling failure killed racks in one us-east-1 zone and a quorum died with them. What the blast radius promise covers, plus a read-only detector for it.
Two Zones, Eighteen Hours, One Cause
Drone strikes put AWS's me-central-1 region into months of recovery and its DR advice was: restore into Europe. Plus a lab mapping AZ names to real IDs.
The Fix Shares Fate With the Outage
Lambda 2023, the DynamoDB DNS event, Azure's February control-plane failure: why recovery paths die with the incident, plus a lab measuring static stability.
Testing the Assumption Nobody Tests
AWS FIS can fail a zone and only approximate losing the control plane. How to run the game day, what to measure, and an honest scorecard for the series.