AWS Availability Zones

Purpose

AWS offers global infrastructure divided into regions and availability zones. This document outlines the AWS availability zones (AZs) used by the NHSBSA BSA Cloud platform.

Requirement

The NHSBSA BSA Cloud platform utilises the following AWS availability zones within the EU (London) region (eu-west-2):

• eu-west-2a
• eu-west-2b
• eu-west-2c

These availability zones are selected to ensure high availability and fault tolerance for services deployed on the BSA AWS Cloud platform.

Services must use at least two availability zones for critical components to ensure redundancy and failover capabilities within production environments. This is to ensure that in the event of an AZ failure, services remain operational.

Non-production environments may use a single availability zone, but it is recommended to use multiple AZs where possible to mimic production setups.

Compliance