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ApsaraDB RDS:Configure automatic storage expansion

Last Updated:Jun 20, 2026

Insufficient database storage can cause write failures, data loss, or even a database crash, severely impacting your business. ApsaraDB RDS for MySQL supports automatic storage expansion when the storage space reaches a specified threshold. This expansion occurs without an instance restart and does not affect your services.

Prerequisites

  • The instance uses the subscription or pay-as-you-go billing method.

    Note

    If the billing method is serverless, the instance storage expands automatically and requires no configuration.

  • The instance is a High-availability Edition or Cluster Edition.

    Note

    For Basic Edition instances that use a cloud disk, you can enable automatic storage expansion in the Database Autonomy Service (DAS) console. For more information, see Automatic space expansion.

  • The instance uses a cloud disk for storage.

  • The instance is in the Running state.

  • Your account has a sufficient balance to cover the expansion.

How it works

When automatic storage expansion is triggered on a primary instance with read-only instances, the system first expands any read-only instance that has less storage than the primary's new target capacity. After all read-only instances are expanded, the system expands the primary instance. For more information, see Optimization of automatic storage expansion rules for ApsaraDB RDS for MySQL and ApsaraDB RDS for PostgreSQL instances.

Procedure

  1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.

  2. On the Basic Information page, in the Instance Resources section, click Settings next to Automatic Storage Expansion.

    Note

    If the Settings button is not displayed, check whether your instance meets the Prerequisites.

  3. Configure the following parameters.

    Parameter

    Description

    Automatic Storage Expansion

    Enables or disables automatic storage expansion.

    Available Storage <=

    The threshold that triggers the expansion. When the percentage of available storage drops to or below this value, an expansion is triggered.

    Note

    The expansion size is the greater of the following two values:

    • 5 GB. If the total storage of the instance is less than 50 GB and the available storage is less than 10%, the expansion increment is adjusted to 10 GB.

    • 15% of the current instance storage, with the result rounded to the nearest multiple of 5.

    For example, for an instance with 100 GB of total storage, 15% of the capacity is 15 GB. Since this amount is greater than 5 GB, the system adds 15 GB when the threshold is met, for a new total capacity of 115 GB.

    Maximum Storage Capacity

    The maximum storage capacity of the instance after expansion. This value must be greater than or equal to the current storage capacity of the instance.

    The maximum capacity varies by cloud disk type. You can set a value within the following ranges:

    • ESSD: 32,000 GB

    • high-performance cloud disk: 64,000 GB

    • standard SSD: 6,000 GB

      Note

      Standard SSDs are discontinued. We recommend that you upgrade to ESSDs.

  4. Click OK.

Related topics

API reference

API

Description

ModifyDasInstanceConfig

Configures automatic storage expansion for an instance.

FAQ

Q: Why can't I find the Settings button for Automatic Storage Expansion in the Usage Statistics section?

A: Your instance must meet all the prerequisites described in this topic. For instances that use a high-performance local SSD, you must manually expand the storage or change the storage type from high-performance local SSD to cloud disk before you can enable automatic storage expansion.