How do I resolve storage space issues in Amazon RDS for PostgreSQL?

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.

Check the resources that use your DB instance storage

If you receive the "No space left on device" or "DiskFull" error message, then check the resources that use your DB instance storage. For more information, see Why did I receive a "No space left on device" or "DiskFull" error on Amazon RDS for PostgreSQL?

Increase your storage capacity

You receive the following error message:

"The specified database instance is currently in storage-full state"

This error occurs when your DB instance is in the storage-full state and you try to modify multiple DB instance parameters. When an instance runs out of storage, Amazon RDS restricts modifications to protect the instance from potential issues.

To increase storage, see Increasing DB instance storage capacity.

You must increase storage by at least 10% of the current size. If you increase the value by less than 10%, then you get an error.

Note: After you allocate more storage, you can't reduce the amount of storage. Instead, you can use Amazon RDS Blue/Green Deployments to decrease your storage volumes. Or, create a new DB instance that has a smaller storage size. For more information, see How do I reduce the storage size and cost of my Amazon RDS database instance? 

Monitor your storage optimization

You receive the following error message:

"Unable to scale the storage for the reason: DB instance is in the cooling-off period for a previous scale storage operation"

This error occurs when you try to modify the storage capacity again less than 6 hours after you first modified the storage. You must wait either 6 hours or until the storage optimization completes, whichever is longer. 

To monitor the progress of your storage optimization, run the following describe-db-instances command:

aws rds describe-db-instances --db-instance-identifier instance-id

Note: Replace instance-id with your database instance ID.

If you must immediately optimize your storage, then perform a point-in-time restore with larger storage allocation. Or, restore from a snapshot with larger storage allocation.

Prevent future storage-full states

To prevent the storage-full state in your DB instance, take the following actions:

• Configure storage autoscaling.
• Create Amazon CloudWatch alarms to monitor the FreeStorageSpace metric.
• Schedule regular VACUUM autovacuum operations to get space from dead tuples.

Modify your maximum storage threshold and allocated storage

You receive the following error message:

"Max storage size must be greater than storage size"

This error occurs when your autoscaling configuration's maximum storage threshold is lower than or equal to the new storage size that you're setting. The autoscaling maximum threshold must be larger than your allocated storage.

To resolve this issue, temporarily turn off storage autoscaling. Then, modify your DB instance settings so that Maximum storage threshold is larger than Allocated storage.

Related information

Working with storage for Amazon RDS DB instances

Best practices for Amazon RDS