Help Center/ Relational Database Service/ User Guide (Ally Region)/ Working with RDS for PostgreSQL/ Instance Modifications/ Scaling Storage Space
Updated on 2026-04-24 GMT+08:00
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Scaling Storage Space

Scenarios

If the storage space is not enough for your workloads, you can scale up storage space of your DB instance.

When the storage usage is greater than or equal to 97%, the DB instance status changes to Storage full. The application's connection to the instance is intermittently interrupted and the instance becomes read-only. If this happens, data cannot be written to the instance.

When the instance status is Storage full, you need to scale up storage space to make the instance preserve at least 15% of its capacity to work properly. You are advised to set alarm rules for the Storage Space Usage metric to learn about the storage usage in a timely manner. For details, see Setting Alarm Rules.

Constraints

Table 1 Constraints

Phase

Constraints

Duration

Storage scale-up
  • Workloads are not interrupted during storage scale-up.
  • The maximum allowed storage is 4,000 GB. There is no limit on the number of scale-ups.
  • For primary/standby DB instances, scaling up the primary DB instance will cause the standby DB instance to also be scaled up.
  • A DB instance cannot be deleted during scale-up.
  • If you scale up the storage of a DB instance with disk encryption enabled, the new storage will still use the original key for encryption.

The scale-up takes 3 to 5 minutes.

Scaling the Storage Space of a DB Instance

  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click in the upper left corner of the page and choose Database > Relational Database Service.
  4. On the Instances page, locate the target DB instance and choose More > Scale Storage Space in the Operation column.
  5. Specify the new storage space and click Next.

    You can increase or decrease the storage by at least 10 GB. Enter a value that is a multiple of 10. The instance supports a storage space range from 40 GB to 4,000 GB.

  6. Confirm the information.

    • If you need to modify your settings, click Previous.
    • If you do not need to modify your settings, click Submit.

  7. Check the result.

    During the scale-up, the instance status on the Instances page will be Scaling up. After a while, click the instance name and view its new storage space on the displayed Basic Information page to verify that the scale-up is successful.

Scaling the Storage Space of a Read Replica

Scaling the storage space of a read replica does not affect that of the primary DB instance. You can separately scale read replicas to meet service requirements. New storage space of read replicas after scaling must be greater than or equal to that of the primary DB instance.

  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click in the upper left corner of the page and choose Database > Relational Database Service.
  4. On the Instances page, locate the target DB instance and click in front of it. Locate the read replica to be scaled and choose More > Scale Storage Space in the Operation column.
  5. Specify the new storage space and click Next.

    You can increase or decrease the storage by at least 10 GB. Enter a value that is a multiple of 10. The instance supports a storage space range from 40 GB to 4,000 GB.

  6. Confirm the information.

    • If you need to modify your settings, click Previous.
    • If you do not need to modify your settings, click Submit.

  7. Check the result.

    During the scale-up, the status of the read replica on the Instances page will be Scaling up. After a while, click the read replica name and view its new storage space on the displayed Basic Information page to verify that the scale-up is successful.

Parent topic: Instance Modifications