Operations → Cloud Infrastructure
Availability Zone
An isolated location within a cloud region designed to limit failure blast radius.
Motivation
An availability zone solves the problem of isolating failures inside a cloud region.
Where it fits
It belongs to cloud infrastructure and reliability design.
Mental model
An availability zone is a separate failure domain within a region, often with independent power, networking, and facilities.
Important details
Multi-AZ designs improve availability by spreading replicas across failure domains.
Common mistakes
- Thinking multi-AZ is the same as multi-region.
- Forgetting cross-zone latency and cost.