A Case Study: When Staging Takes Down Prod
A small incident on Reddit caught my attention. A harmless Redis serialization refactor accidentally wrote incompatible data to a shared cache. Because staging and production used the same Redis instance, staging corrupted production values. Prod couldn’t deserialize them, fell back to the database, hammered it with full table scans and p99 latency spiked.
The interesting part isn’t the bug. It’s how typical this pattern is. If your production relies only on engineers that never make mistakes — your system is already broken.
High reliability engineering assumes two things:
People will make mistakes
Systems must be designed so those mistakes don’t become incidents
Design for the reality of human error and everybody will thank you later.