Availability Zone (AZ)
#3 · Level 0 · Getting started · Cloud basicsConcept
Section titled “Concept”An Availability Zone (AZ) is one of the separate data centers (or groups of data centers) inside a Region. Each AZ has its own power, cooling and network. A problem in one AZ usually does not affect the other AZs. The AZs in the same Region are connected to each other by a high-speed network. So spreading things like EC2, Subnets and Load Balancers across several AZs makes an app more reliable (high availability).
Simple example
Section titled “Simple example”A bank has three offices in three separate buildings in Dhaka. Each has its own power, internet and security. Even if one building has a problem, the other two keep working.
Why it’s needed
Section titled “Why it’s needed”So that a problem in one data center (a power cut, a flood, a fire) does not stop the whole system. If you run your app in several AZs, it keeps running even when one of them goes down.
Where it’s used
Section titled “Where it’s used”The servers of an important website are placed in two or three AZs. A copy of a database is kept in another AZ. Each Region usually has three or more AZs, connected by a very fast network.
Azure equivalent
Section titled “Azure equivalent”Azure Availability Zones
Related
Section titled “Related”Learn more
Section titled “Learn more”For details and the latest information, see the official documentation: