What Is AZ and How Can I Select an AZ?

AZ

An AZ is a part of a physical region with its own independent power supply and network. An AZ is generally an independent physical equipment room, ensuring independence of the AZ.

Each region contains multiple AZs. If one AZ becomes faulty, the other AZs in the same region can continue to provide services.

AZs in the same region can communicate with each other over an intranet.

Selecting an AZ

You can deploy your instances in different AZs for high availability. If one of an AZ becomes faulty, databases in other AZs will not be affected. When selecting AZs:

• If only one AZ is available in a region, there is only one AZ in the region.
• The AZ of a purchased DB instance cannot be changed.
• The AZs in one region can communicate with each other over an intranet.

For more information, see Regions and AZs.