Designing Data-Intensive Applications: The Big Ideas Behind Reliable, Scalable, and Maintainable Systems

by Martin Kleppmann

Many services are now expected to be highly available; extended downtime due to outages or maintenance is becoming increasingly unacceptable.

To be fair, though, not all services need to be that reliable. No one's health, life or livelihood is going to be adversely impacted by a sporadic timeout.