Availability Zone
An isolated data center within a cloud region, with independent power, cooling, and networking. Deploying across multiple AZs protects against single-facility failures.
What is Availability Zone?
An isolated data center within a cloud region, with independent power, cooling, and networking. Deploying across multiple AZs protects against single-facility failures.
Availability Zone is a intermediate-level concept that sits in the Cloud Infrastructure area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Availability Zone" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
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See also
Related glossary terms you might want to look up next.
Cloud Region
A geographic area containing one or more data centers (availability zones). Choosing the right region reduces latency and satisfies data residency requirements.
Fault Tolerance
A system's ability to keep operating correctly even when some of its components fail. Achieved through redundancy, replication, and graceful degradation.
Redundancy
Duplicating critical components or functions so that if one fails, a backup takes over. The reason planes have two engines and databases have replicas.