Configuring Autoscaling

You can enable storage autoscaling for GeminiDB Cassandra instances. When the storage space usage reaches the upper limit, autoscaling is triggered.

You can enable storage autoscaling:

When you create an instance. For details, see Buying an Instance.
After you create an instance

This section describes how to configure storage autoscaling after an instance is created.

Configuring the Required Permissions

If you are an IAM user, perform the following operations before you enable storage autoscaling:

Configure fine-grained permissions for IAM and minimum permissions for GeminiDB.

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

{
    "Version": "1.1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "iam:permissions:grantRoleToAgencyOnDomain",
                "iam:permissions:grantRoleToAgencyOnProject",
                "iam:agencies:listAgencies",
                "iam:roles:listRoles",
                "iam:agencies:getAgency",
                "iam:agencies:createAgency",
                "iam:permissions:checkRoleForAgencyOnProject",
                "iam:permissions:listRolesForAgency",
                "iam:quotas:listQuotas",
                "iam:permissions:checkRoleForAgencyOnDomain",
                "iam:permissions:revokeRoleFromAgencyOnProject",
                "iam:permissions:grantRoleToAgency",
                "iam:permissions:listRolesForAgencyOnProject",
                "iam:agencies:updateAgency",
                "iam:permissions:revokeRoleFromAgency",
                "iam:permissions:checkRoleForAgency",
                "iam:permissions:revokeRoleFromAgencyOnDomain",
                "iam:agencies:deleteAgency",
                "iam:permissions:listRolesForAgencyOnDomain",
                "nosql:instance:list",
                "nosql:instance:modifyStorageSize"
            ]
        }
    ]
}

Create a user group and assign permissions.
You can create a user group on the IAM console and grant it the permissions created in 1.
Create an IAM user and add it to a user group.
Log in to the IAM console using the major account or an account with the IAM permissions, 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 when your account balance is sufficient.
Autoscaling is currently in open beta testing. If you need to use this function, contact customer service to apply for it.
The instance is in the Available status.
Once autoscaling is enabled, an agency will be created and fees will be automatically deducted.

Autoscaling of a Single Instance

Log in to the management console.
In the service list, choose Databases > GeminiDB.
On the Instances page, click the instance. The Basic Information page is displayed.
In the Storage Space area, click Configure Autoscaling.

Figure 1 Configure Autoscaling

Enable the Configure Autoscaling toggle and specify the trigger condition, increment, and autoscaling limit.

Figure 2 Configuring autoscaling parameters

**Table 1** Parameter description
Parameter	Description
Configure Autoscaling	The autoscaling toggle button.
Trigger If Available Storage Drops To	When the available storage drops to a specified threshold or 10 GB, autoscaling is triggered.
Increment	The percentage of the current storage to be automatically scaled. The value can be 10, 15, or 20. You can select a proper increment as required. At least 100 GB is added each time.
Storage Space	Upper limit of the storage space in GB that can be automatically scaled to The limit must be no less than the storage of your instance and cannot exceed the maximum storage space defined by your instance specifications.

Click OK.

Autoscaling Storage Space of Instances in Batches

Log in to the management console.
In the service list, choose Databases > GeminiDB.
Select instances and click Auto Scale.

Figure 3 Storage autoscaling

Select the instance for which you want to configure autoscaling, enable autoscaling, and specify the trigger conditions and autoscaling limit.

Figure 4 Configuring autoscaling parameters

**Table 2** Parameter description
Parameter	Description
Configure Autoscaling	The autoscaling toggle button.
Trigger If Available Storage Drops To	When the available storage drops to a specified threshold or 10 GB, autoscaling is triggered.
Increment	Preset percentage of currently allocated storage. You can choose to set it to 10, 15, or 20 based on service requirements. At least 100 GB is added each time.
Storage Space	Batch autoscaling does not allow you to specify an upper storage limit. The upper limit is the maximum storage defined by your instance specifications by default.