Why is my Amazon RDS DB instance in the storage-optimization state for a long time?

Resolution

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.

When you modify the storage size of your DB instance, the instance enters the storage-optimization state. Amazon RDS automatically performs the storage optimization process. Amazon RDS evenly distributes the data to the Amazon Elastic Block Store (Amazon EBS) volumes after storage modification.

In most cases, scaled storage doesn't cause an outage or performance degradation of the DB instance. However, the operation might take several hours. You can't make further storage modifications for either 6 hours or until storage optimization completes on the instance, whatever is longer. You can perform any other instance modifications, such as scaling instance size or performing a reboot. After you scale the instance, you can see the storage optimization progress in the AWS Management Console or use the describe-db-instances AWS CLI command.

Typically, storage optimization completes in a few hours, but the process can take more than 24 hours. The instance is operational during storage optimization and your application is still available. You can run your applications during storage optimization.

Note: You can't speed up storage optimization and must wait for the process to complete. The process takes longer for larger storage size increases and storage usage. Because it's an automated process, there's no fixed way to determine how long it takes to complete storage optimization on your instance.

For a cluster volume, Amazon Aurora uses a custom storage solution for data and Amazon EBS for local storage. When you scale DB instances, for example from db.r5.2xlarge to db.r5.4xlarge, you can see storage optimization events in the status column.

Note: If you make any type of storage modification, then the instance enters the storage-optimization state. When you modify the storage, the instance might restart. This is a requirement in specific cases, such as a change to the storage type between SSD and magnetic. For more information, see Settings for DB instances.

To monitor the amount of free storage for your DB instance, it's a best practice to create an Amazon CloudWatch alarm.

Related information

Managing an Amazon RDS DB instance