Curriculum
Module 06
State and Consistency
The layer that makes deployment hard, taught from the Cambridge distributed systems course.
5 lessons · 3 videos · 1h 24m
- 06.01
Why State Ruins Everything
State the system model and failure model you are working under, because every guarantee below depends on which one you assumed.
- 06.02
Databases Under Load
Apply Little's Law to a connection pool and explain why the pool, not the query, is usually the bottleneck.
- 06.03
Replication and Consistency
Say what a replica guarantees, and why a read can be behind the write you just made.
- 06.04
Consensus
Explain leader election and log replication, why R + W > N matters, and why three replicas rather than two.
- 06.05
Migrations Against Live Traffic
Run an expand-contract migration and name the exact window in which rollback stops being possible.