The Standup Casey breaksdown AWS outage (Whiteboard Edition)
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Jan 13, 2026 
Casey Muratori, a renowned software engineer and developer-educator, dives deep into the recent AWS/DynamoDB outage. He emphasizes the need for genuine understanding of outages, dissecting the failure of the RCA to teach engineers effectively. Casey explains the intricate workings of DNS routing, load-balancing, and enactor roles, revealing how a single missing rollback record caused a massive service crash. He speculates on the potential coding mistakes and underscores the importance of thorough analysis to build trust and confidence in engineering.
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Understand, Don't Pretend To Understand
- Casey stresses the difference between saying you understand something and actually understanding it by asking clarifying questions.
- He argues that admitting ignorance and investigating deeply prevents future mistakes and bad assumptions.
Simple Bugs Cause Big Failures
- High-profile outages often have simple root causes like null dereferences or array overflows.
- Clear RCAs that show the exact failing code help engineers learn and avoid repeating mistakes.
Unclear Design Hurt The RCA's Usefulness
- Casey reconstructs DynamoDB's Route 53 load‑balancing “plan” workflow with a single planner and three enactors.
- He highlights missing explanations in AWS's presentation about why that architecture and locking exist.