Database Autonomy Service:Automatic space expansion

Usage notes

• If a database instance has read-only instances and automatic space expansion is triggered for the primary instance, the system checks the storage space of each read-only instance. If the storage space of a read-only instance is smaller than the target storage space of the primary instance after the expansion, the system expands the storage of the read-only instance first. After the storage of all read-only instances is expanded, the system then expands the storage of the primary instance.

• Because of Windows driver limitations, this feature is unavailable for some instances. We recommend that you upgrade the minor engine version of SQL Server.

Billing

The billing rules for automatic space expansion are the same as those for manually upgrading the storage space of an RDS instance. For more information, see Billing for specification changes.

Procedure

1. Log on to the DAS console.

2. In the left-side navigation pane, choose Intelligent O&M Center > Instance Monitoring.

3. On the page that appears, find the database instance that you want to manage and click the instance ID. The instance details page appears.

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

5. In the upper-right corner of the Autonomy Center page, click Autonomy Service Settings.

6. On the Autonomous Function Management > Autonomous Function Settings tab, turn on the autonomous function switch.

7. On the Optimization and Throttling tab, select Automatic Space Expansion and configure the parameters described in the following table.

   Parameter	Description
   Available Storage Space ≤	The threshold for scaling out. When the available storage space of your instance is less than or equal to the threshold you set, the system scales out the storage by the larger of the following two values: 5 GB. Note If the total storage space of the instance is less than 50 GB and the available storage space is less than 10% of the total storage space, the scaling step size is adjusted to 10 GB. 15% of the current total storage space of the instance. The result is rounded to the nearest multiple of 5. For example, if the current total storage space is 100 GB, 15% of this is 15 GB, which is greater than 5 GB. When the threshold is reached and a scale-out is triggered, 15 GB of storage is added. After the scale-out, the total storage space is 115 GB. Note For PolarDB for MySQL Standard Edition instances, the scale-out threshold is set by default and does not need to be configured. For more information about the threshold, see Scale-out thresholds for PolarDB for MySQL Standard Edition.
   Maximum Storage of Automatic Expansion	The maximum total storage space of the instance after a scale-out. This value must be greater than or equal to the current total storage space of the instance. Important For PolarDB for MySQL Standard Edition database instances, the scaling step size is an integer multiple of 10. We recommend that you set the Maximum Storage of Automatic Expansion to an integer multiple of 10. Otherwise, the scale-out may fail or the storage may fail to reach the specified Maximum Storage of Automatic Expansion.

   Note

   The minimum interval between two space expansion operations is 10 minutes.

8. Click OK.

9. Configure an Alert Template and subscribe to alerts to receive timely notifications about the status of automatic storage expansion for your database instance.

   The system recommends an alert template and adds alert rules for the corresponding autonomy events. You can perform the configuration as prompted.

   Note

   • If you have already configured an alert template for the instance, add alert rules for the corresponding autonomy events to the template as prompted.

   • To set the alert template and alert rules yourself, see Configure alert templates and Configure alert rules.

10. Select an Alert Contact Group to receive alert notifications.

    • Click Add Contact to add a new alert contact.

    • Click Create Contact Group to create an alert contact group.

    • Click Edit or Remove next to the target contact to modify or delete its information.

    For more information, see Manage alert contacts.

11. Click Submit Configuration. In the dialog box that appears, confirm the alert configuration.

View the results of automatic space expansion

1. Log on to the DAS console.

2. In the left-side navigation pane, choose Intelligent O&M Center > Instance Monitoring.

3. On the page that appears, find the database instance that you want to manage and click the instance ID. The instance details page appears.

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

5. On the Autonomy Center page, view the Auto-Scaling Events that occurred within the selected time range.

6. Click Details to view the details of automatic storage expansion.

Scale-out thresholds for PolarDB for MySQL Standard Edition

The scale-out threshold is related to the total storage space of the database instance, as shown in the following table:

References

• After the storage space is automatically expanded, automatic scale-in is not supported. To scale in the storage, you must manually change the configuration. For more information, see Change instance configurations.

  Note

  Manual scale-in is not supported for RDS SQL Server and PolarDB for MySQL Standard Edition instances.

• You can enable automatic fragment reclamation to clear tablespace fragments and reduce wasted storage space.

• You can use the storage analysis and capacity assessment features to view and analyze storage usage.

• If the database instance is an RDS PostgreSQL instance, see Automatic storage expansion.

• If the database instance is a PolarDB for MySQL instance, see Set automatic storage expansion for ESSDs.