Regions and Availability Zones

Amazon cloud computing resources are hosted in multiple locations world-wide. These locations are composed of AWS Regions and Availability Zones. Each AWS Region is a separate geographic area. Each AWS Region has multiple, isolated locations known as Availability Zones.

Amazon operates state-of-the-art, highly-available data centers. Although rare, failures can occur that affect the availability of DB instances that are in the same location. If you host all your DB instances in one location that is affected by such a failure, none of your DB instances will be available.

It is important to remember that each AWS Region is completely independent. Any Amazon RDS activity you initiate (for example, creating database instances or listing available database instances) runs only in your current default AWS Region. The default AWS Region can be changed in the console, or by setting the AWS_DEFAULT_REGION environment variable. Or it can be overridden by using the --region parameter with the AWS Command Line Interface (AWS CLI). For more information, see Configuring the AWS Command Line Interface, specifically the sections about environment variables and command line options.

Amazon RDS supports special AWS Regions called AWS GovCloud (US). These are designed to allow US government agencies and customers to move more sensitive workloads into the cloud. The AWS GovCloud (US) Regions address the US government's specific regulatory and compliance requirements. For more information, see What is AWS GovCloud (US)?

To create or work with an Amazon RDS DB instance in a specific AWS Region, use the corresponding regional service endpoint.

AWS Regions

Each AWS Region is designed to be isolated from the other AWS Regions. This design achieves the greatest possible fault tolerance and stability.

When you view your resources, you see only the resources that are tied to the AWS Region that you specified. This is because AWS Regions are isolated from each other, and we don't automatically replicate resources across AWS Regions.

Region availability

When you work with an Aurora DB cluster using the command line interface or API operations, make sure that you specify its regional endpoint.

Aurora MySQL Region availability

The following table shows the AWS Regions where Aurora MySQL is currently available and the endpoint for each Region.

Aurora PostgreSQL Region availability

The following table shows the AWS Regions where Aurora PostgreSQL is currently available and the endpoint for each Region.

Availability Zones

An Availability Zone is an isolated location in a given AWS Region. Each Region has multiple Availability Zones (AZ) designed to provide high availability for the Region. An AZ is identified by the AWS Region code followed by a letter identifier (for example, us-east-1a). If you create your VPC and subnets rather than using the default VPC, you define each subnet in a specific AZ. When you create an Aurora DB cluster, Aurora creates the primary instance in one of the subnets in the VPC's DB subnet group. It thus associates that instance with a specific AZ chosen by Aurora.

Each Aurora DB cluster hosts copies of its storage in three separate AZs selected automatically by Aurora from the AZs in your DB subnet group. Every DB instance in the cluster must be in one of these three AZs.

When you create a DB instance in your cluster, Aurora automatically chooses an appropriate AZ for that instance if you don't specify an AZ.

Use the describe-availability-zones Amazon EC2 command as follows to describe the Availability Zones within the specified Region that are enabled for your account.

aws ec2 describe-availability-zones --region region-name

For example, to describe the Availability Zones within the US East (N. Virginia) Region (us-east-1) that are enabled for your account, run the following command:

aws ec2 describe-availability-zones --region us-east-1

To learn how to specify the AZ when you create a cluster or add instances to it, see Configure the network for the DB cluster.

Local time zone for Amazon Aurora DB clusters

By default, the time zone for an Amazon Aurora DB cluster is Universal Time Coordinated (UTC). You can set the time zone for instances in your DB cluster to the local time zone for your application instead.

To set the local time zone for a DB cluster, set the time zone parameter to one of the supported values. You set this parameter in the cluster parameter group for your DB cluster.

When you set the time zone parameter for a DB cluster, all instances in the DB cluster change to use the new local time zone. In some cases, other Aurora DB clusters might be using the same cluster parameter group. If so, all instances in those DB clusters change to use the new local time zone also. For information on cluster-level parameters, see Amazon Aurora DB cluster and DB instance parameters.

After you set the local time zone, all new connections to the database reflect the change. In some cases, you might have open connections to your database when you change the local time zone. If so, you don't see the local time zone update until after you close the connection and open a new connection.

If you are replicating across AWS Regions, the replication source DB cluster and the replica use different parameter groups. Parameter groups are unique to an AWS Region. To use the same local time zone for each instance, make sure to set the time zone parameter in the parameter groups for both the replication source and the replica.

When you restore a DB cluster from a DB cluster snapshot, the local time zone is set to UTC. You can update the time zone to your local time zone after the restore is complete. In some cases, you might restore a DB cluster to a point in time. If so, the local time zone for the restored DB cluster is the time zone setting from the parameter group of the restored DB cluster.

The following table lists some of the values to which you can set your local time zone. To list all of the available time zones, you can use the following SQL queries: