Database Autonomy Service (DAS) monitors the storage space of a database instance and can automatically expand the storage space to ensure business stability. This topic describes how to enable the Automatic Space Expansion feature.


  • An ApsaraDB RDS instance that uses standard SSDs or enhanced SSDs (ESSDs) is connected to DAS.
  • Enable Autonomy Service is turned on for the database instance. For more information, see Autonomy center.

Background information

For more information about the background, see AutoScale.
Note After the storage space is expanded, you cannot reduce it.


  1. Log on to the DAS console.
  2. In the left-side navigation pane, click Instance Monitoring.
  3. On the Instance Monitoring page, find the instance for which you want to enable automatic space expansion, and click the instance ID to go to the instance details page.
  4. In the left-side navigation pane, click Autonomy Center.
  5. On the Autonomy Center page, click Autonomous function switch in the upper-right corner.
  6. In the Set dialog box, turn on Automatic Space Expansion.
  7. Enter the maximum storage space in the Maximum Storage of Automatic Expansion field.
    Note The billing rules are the same as those for manually expanding the storage space of an ApsaraDB RDS instance. For more information, see Specification change fees.
  8. Click Determine.