Automatic storage expansion

Limitations

• Expanded storage cannot be automatically scaled down. To decrease the storage size, you must manually change instance specifications.

• Since February 28, 2023, the automatic storage expansion rules have been updated. Now, if an expansion is triggered on a primary instance with attached read-only instances, the system first expands any read-only instance whose storage is less than the primary instance's target size. After all applicable read-only instances are expanded, the system expands the primary instance. For more information, see [Notice] Optimization of automatic storage expansion rules for ApsaraDB RDS for MySQL and ApsaraDB RDS for PostgreSQL instances.

• If an expansion is triggered while an instance is being backed up, the expansion task waits for the backup to finish.

Billing

The billing for automatic storage expansion is the same as for manually expanding an RDS instance's storage. For more information, see Billing rules for specification changes.

Procedure

1. Log on to the DAS console.

2. Add an automatic storage expansion policy.

   • Add a policy from the Management and Settings page.

     1. In the navigation pane on the left, choose Resource Management > Auto Scaling Settings.

     2. On the right side of the Auto Scaling Policies section, click Add Policy. On the Add Policy page, set the following parameters:

        Table 1. Parameters

        Parameter	Description
        Policy Name	The name of the policy.
        Mode	The mode of the policy. Select Automatic Storage Expansion.
        Engine Type	The database engine type. Currently, only ApsaraDB RDS for PostgreSQL is supported.
        Specifications	The specification of the database engine. Currently, only the Disks edition is supported.
        Used Storage Space ≥	The storage usage threshold, as a percentage of total storage. Valid values: 50% to 90%. Default value: 50%. When usage meets or exceeds this threshold, the system expands the storage by the larger of the following two values: 5 GB Note If the total storage of the instance is less than 50 GB and its available storage is less than 10%, the scaling increment is adjusted to 10 GB. 15% of the instance's total storage (the result is rounded to the nearest multiple of 5). Note The minimum interval between two consecutive storage expansions is 10 minutes.
        Maximum Storage	The upper limit for automatic storage expansion. This value must be greater than or equal to the current total storage of the target instance. ESSD limit: 32,000 GB Standard SSD limit: 6,000 GB

     3. Click Next.

     4. On the Apply Policies page, select the desired database instances and then click .

     5. Click Confirm to apply the policy.

   • For the instance's Autonomy Service Settings, add an automatic storage expansion policy on its Autonomous Function Management page.

     1. In the navigation pane on the left, choose Intelligent O&M Center > Instance Monitoring.

     2. Find the target instance and click its instance ID to go to the instance details page.

     3. In the upper-right corner, click Autonomy Service Settings.

     4. In the panel that appears, go to the Autonomous Function Management > Autonomous Function Settings > Auto Scaling tab, click Add Policy, and configure the parameters as described in Parameters to create a new automatic storage expansion policy.

     5. In the Recommended Policies section, find the policy you want to add and click Apply in the Actions column to apply the policy to the instance.

        Note

        • Click Apply in the Actions column for a policy in the Recommended Policies section to add the policy to the instance.

        • To remove a policy, find it in the Applied Policies section and click Cancel in the Actions column.

     6. Click OK.

     7. Configure an Alert Template to receive notifications about automatic storage expansions.

        The system automatically sets up a corresponding alert template and adds alert rules for related autonomous events. If you need to configure them manually, see Configure alert templates and Configure alert rules.

     8. Select an Alert Contact Group to receive notifications.

        • Click Add Contact to add a new alert contact.

        • Click Add Contact Group to create a new alert contact group.

        • To modify or delete an existing contact, click Modify or Remove next to the contact.

        For detailed instructions, see Manage alert contacts.

     9. Click Submit Configuration and confirm the alert settings in the dialog box that appears.

View expansion results

1. In the navigation pane on the left, choose Intelligent O&M Center > Instance Monitoring.

2. Find the target instance and click its instance ID to open the instance details page.

3. In the navigation pane on the left, click Autonomy Center.

4. On the Autonomy Center page, view the Elastic Scaling Events for the selected time range.

5. Click Details for an Elastic Scaling Events to view its details.

   The elastic scaling event card displays information such as Occurrence Time, Severity, and Duration.

Related documents

DAS Auto Scaling