How do I minimize downtime during required Amazon RDS maintenance?

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Note: If you receive errors when you run AWS Command Line Interface (AWS CLI) commands, then see Troubleshooting errors for the AWS CLI. Also, make sure that you're using the most recent AWS CLI version.

Occasionally, AWS performs maintenance to the hardware, operating system (OS), or database engine version for a DB instance or cluster. For more information, see Maintaining a DB instance.

To view pending maintenance events, you can use the AWS Management Console, describe-pending-maintenance-actions AWS CLI command, or DescribePendingMaintenanceActions API.

Hardware maintenance

Before Amazon RDS performs maintenance, you receive an email notification about the scheduled maintenance windows. The notification includes the time of the maintenance and the affected Availability Zones. During hardware maintenance, Single-AZ deployments are unavailable for a few minutes. For Multi-AZ deployments with an affected primary Availability Zone, your deployment is unavailable for the time that the instance takes to fail over. The failover usually takes about 60 seconds. If maintenance affects only the secondary Availability Zone, then there's no failover or downtime.

OS maintenance

To postpone scheduled OS maintenance, adjust your preferred maintenance window. Or, choose Defer upgrade from the Actions menu in the Amazon RDS console. To minimize downtime, modify the Amazon RDS DB instance to a Multi-AZ deployment. For Multi-AZ deployments, OS maintenance applies to the secondary instance. The instance fails over, and then the primary instance updates. The downtime is during failover. For more information, see Maintenance for Multi-AZ deployments.

Note: If you upgrade to a Multi-AZ deployment, then you incur higher costs. To determine your costs, use the AWS Pricing Calculator.

DB engine maintenance

Upgrades to your database engine version require downtime. Even when your RDS DB instance uses a Multi-AZ deployment, both the primary and standby DB instances upgrade simultaneously. Downtime occurs until the upgrade completes. The duration of the downtime varies based on the size of your DB instance.

For more information about your specific DB engine, see the following documentation:

• Upgrades of the MariaDB DB engine

• Upgrades of the Microsoft SQL Server DB engine

• Upgrades of the RDS for MySQL DB engine

• Upgrading the RDS for Oracle DB engine

• Upgrades of the RDS for PostgreSQL DB engine

If the instance is a read replica, then the upgrade occurs independently from the source instance. By default, maintenance occurs first on the primary instance and then on the replica.

Related information

Using a read replica to reduce downtime when upgrading an RDS for MySQL database

What happens to Amazon RDS and Amazon Redshift queries that are running during a maintenance window?

How do I configure notifications for Amazon RDS or Amazon Redshift maintenance windows?