availabilityzone

An availability zone, often abbreviated as AZ, is a distinct physical location within a cloud provider's region. Regions are geographic areas like "us-east-1" or "eu-west-2", and within each region, there are multiple isolated availability zones. The primary purpose of availability zones is to provide high availability and fault tolerance for applications and data.

Each availability zone is an independent environment with its own power, cooling, and networking infrastructure. This isolation ensures that if one availability zone experiences an outage, such as a power failure or a natural disaster, other availability zones in the same region remain operational. Cloud services can be deployed across multiple availability zones to achieve resilience.

By distributing resources, such as virtual machines, databases, and storage, across different availability zones, a failure in one zone will not disrupt the entire application. If a resource in one AZ becomes unavailable, traffic can be automatically redirected to equivalent resources in another healthy AZ. This redundancy is a core tenet of modern cloud architectures for ensuring business continuity and minimizing downtime. Users typically choose which availability zones to deploy their services in to control their availability and latency.