Help Center/ Document Database Service/ User Guide/ Instance Modifications/ Scaling Up Storage Space/ Configuring Storage Autoscaling for a DB Instance
Updated on 2026-05-20 GMT+08:00
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Configuring Storage Autoscaling for a DB Instance

Scenarios

With storage autoscaling enabled, when DDS detects that you are running out of database space, it automatically scales up your storage.

This section describes how to configure an autoscaling policy after a DDS instance is created.

Configuring Permissions

If you are using an IAM user, configure DDS and IAM permissions before you enable storage autoscaling. The procedure is as follows:
  1. Configure the DDS FullAccess permission of DDS.
  2. Configure fine-grained permissions of IAM.

    For details about how to configure IAM permissions, see Creating a Custom Policy.

    {
     "Version":"1.1",
     "Statement":[
         {
             "Effect":"Allow",
             "Action":[
                 "iam:permissions:listRolesForAgencyOnProject",
                 "iam:permissions:grantRoleToGroupOnProject",
                 "iam:agencies:createAgency",
                 "iam:agencies:listAgencies",
                 "iam:roles:listRoles",
                 "iam:roles:createRole"
             ]
         }
     ]
 }
  3. Create a user group and assign permissions to it.

    You can create a user group on the IAM console and grant it custom permissions created in 2 and the security administrator role.

  4. Add a user to a user group.

    Log in to the IAM console using a Huawei Cloud account or an IAM account, locate the IAM user that the target instance belongs to, and add it to the user group created in 2. The IAM user will inherit permissions of the user group.

Precautions

  • Autoscaling is available only when your account balance is sufficient.
  • If a yearly/monthly DB instance has pending orders, it will not be autoscaled.
  • This function is available only for replica set and cluster instances.
  • The storage space can be autoscaled up only when your instance status is Available or Storage full.
  • If a replica set instance has fewer than 8 vCPUs, the maximum storage that can be autoscaled up to is 5,000 GB. If a replica set instance has 8 or more vCPUs, the maximum storage that can be autoscaled up to is 10,000 GB. If any shard node in a cluster instance has fewer than 8 vCPUs, the maximum storage that can be autoscaled up to is 5,000 GB. If each shard node in a cluster instance has 8 or more vCPUs, the maximum storage that can be autoscaled up to is 10,000 GB.
  • Storage autoscaling is unavailable when the DB instance is in any of the following statuses: changing instance class, upgrading a minor version, or restarting.
  • Replica set and cluster instances with read replicas do not support this function.
  • Before enabling storage autoscaling, you need to . This agency is visible to you. Deleting the agency will result in storage autoscaling failures.

Procedure

  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 Databases > Document Database Service.
  4. On the Instances page, click the target instance. The Basic Information page is displayed.
  5. In the Storage Space area, click Autoscaling.

    Figure 1 Autoscaling

  6. Toggle on Autoscaling and specify the parameters below.

    Figure 2 Configuring autoscaling
    Table 1 Parameter description

    Parameter

    Description

    Autoscaling

    If you toggle on this switch, autoscaling is enabled.

    Storage Usage

    Specifies the threshold for triggering autoscaling. The value can be 80%, 85%, or 90%. If the storage usage is greater than or equal to a specified threshold, autoscaling is triggered. This parameter of a cluster instance applies to each shard node in the instance.

    Increase by

    Percentage that your instance storage will be scaled up at. The value can be 10%, 15%, or 20%. If the value is not a multiple of 10, it is rounded up. The value after the decimal point is rounded. The minimum step is 10 GB by default. If your account balance is insufficient, the yearly/monthly instance will fail to be scaled up.

    Autoscaling Limit

    Maximum storage allowed. If a replica set instance has fewer than 8 vCPUs, the maximum storage that can be autoscaled up to is 5,000 GB. If a replica set instance has 8 or more vCPUs, the maximum storage that can be autoscaled up to is 10,000 GB. If any shard node in a cluster instance has fewer than 8 vCPUs, the maximum storage that can be autoscaled up to is 5,000 GB. If each shard node in a cluster instance has 8 or more vCPUs, the maximum storage that can be autoscaled up to is 10,000 GB.

  7. Click OK.
Parent Topic: Scaling Up Storage Space