This topic describes how to change the specifications of a cluster to meet your business requirements.


You can change cluster specifications only when the cluster does not have pending specification changes.

Background information

PolarDB supports capacity scaling in three dimensions:

  • Vertical scaling of computing capabilities: Upgrade or downgrade the specifications of a cluster. This topic describes the details about this scaling.
  • Horizontal scaling of computing capabilities: Add or remove read-only nodes. For more information, see Add or remove a read-only node.
  • Horizontal scaling of storage capacity: The storage capacity is provisioned in a serverless model. As your data increases in size, the storage is automatically expanded.

This topic describes how to upgrade or downgrade the specifications of a PolarDB cluster. It takes only 5 to 10 minutes for the new specifications of each node to take effect.

Specification change fees

For more information, see Configuration change fees.


  • Specification upgrades or downgrades apply to only clusters. You cannot change specifications of a node.
  • Specification upgrades or downgrades do not affect the existing data in the cluster.
  • We recommend that you modify cluster specifications during off-peak hours. During a specification upgrade or downgrade, the PolarDB service will be disconnected for a few seconds and some features will be disabled. Make sure that your applications can reconnect to the cluster after the disconnection.


  1. Log on to the PolarDB console.
  2. In the upper-left corner of the console, select the region where the cluster is deployed.
  3. Go to the Change Configurations page. You can use the following methods to change the specifications:
    • Find the cluster and click Change Configurations in the Actions column.Clusters
    • Find the cluster, click the cluster ID, and then click Change Configurations in the Database Nodes section.Change Configurations
  4. In the dialog box that appears, select Upgrade or Downgrade, and click OK.
    Change Configurations
  5. Select specifications.
    Note All nodes in a cluster have the same specifications.
  6. Read the service agreement, select the check box, click Buy Now, and then pay for the order.
    Note It takes about 10 minutes for the new specifications to take effect.

Related API operations

API Description
ModifyDBNodeClass Changes the node specifications of a PolarDB cluster.