You can use Database Autonomy Service (DAS) to monitor the storage of your database instance. If the storage space is insufficient, DAS can automatically expand the storage space to ensure the stability of your business.
Prerequisites
The database instance for which you want to enable automatic space expansion is of one of the following types:
ApsaraDB RDS for MySQL instances of Basic Edition that use standard SSDs or enhanced SSDs (ESSDs), of High-availability Edition that use standard SSDs or ESSDs, and of Cluster Edition that use standard SSDs or ESSDs
ApsaraDB MyBase for MySQL instances of High-availability Edition that use standard SSDs or ESSDs
ApsaraDB RDS for SQL Server instances of High-availability Edition that use standard SSDs or ESSDs and of Cluster Edition that use standard SSDs or ESSDs
NoteARM-based ApsaraDB RDS for MySQL instances are not supported.
Read-only instances of ApsaraDB RDS for SQL Server do not support automatic space expansion.
For more information about how to expand the storage space of an ApsaraDB RDS for PostgreSQL instance, see Automatic storage expansion.
The balance of your Alibaba Cloud account is sufficient to pay for the resources that are required to expand storage space.
A service-linked role is created for DAS. For more information, see AliyunServiceRoleForDAS role.
NoteIf the service-linked role is not created and you enable the automatic space expansion feature, the system automatically creates the service-linked role before the system expands storage space.
Background information
For more information, see Auto Scaling.
Usage notes
If your database instances include read-only instances, DAS automatically checks the storage space of each read-only instance when automatic space expansion is triggered for the primary instance. If the storage space of a read-only instance is smaller than that of the primary instance after the storage space of the primary instance is expanded, DAS first expands the storage space of the read-only instance. When the storage space of all read-only instances meets the requirement, DAS automatically expands the storage space of the primary instance.
The automatic space expansion feature cannot be used for some ApsaraDB RDS for SQL Server instances due to the restrictions of Windows drivers. In this case, we recommend that you update the minor engine version of these database instances. For more information, see Update the minor engine version of an ApsaraDB RDS for SQL Server instance.
After the storage space of your database instance is expanded, the storage space cannot be automatically reduced. However, you can manually reduce the storage space by changing the instance specifications. For more information, see Change instance specifications.
NoteYou cannot manually reduce the storage space of ApsaraDB RDS for SQL Server instances.
Billing
The billing rules for automatic space expansion are the same as those for manual storage expansion of ApsaraDB RDS instances. For more information, see Specification changes.
Procedure
Log on to the DAS console.
In the left-side navigation pane, click Instance Monitoring.
On the page that appears, find the database instance that you want to manage and click the instance ID. The instance details page appears.
In the left-side navigation pane, click Autonomy Center.
On the Autonomy Center page, click Autonomy Service Settings in the upper-right corner.
On the Autonomous Function Settings tab of the panel, turn on the switch for the autonomy service.
On the Optimization and Throttling tab, select Automatic Space Expansion and configure the parameters that are described in the following table.
Parameter
Description
Available Storage Space ≤
The storage space threshold for triggering automatic space expansion. If the available storage space of your database instance is less than or equal to the storage space threshold specified by the Available Storage Space parameter, the system automatically expands the storage by adding the following size of space, whichever is larger:
5 GB
15% of the current storage space of the instance
Maximum Storage of Automatic Expansion
The maximum storage capacity that is allowed for automatic space expansion. The value of this parameter must be greater than or equal to the current storage space of your database instance.Maximum Storage of Automatic Expansion
NoteThe interval between two storage expansions is at least 10 minutes.
Click OK.
View the results of automatic space expansion
Log on to the DAS console.
In the left-side navigation pane, click Instance Monitoring.
On the page that appears, find the database instance that you want to manage and click the instance ID. The instance details page appears.
In the left-side navigation pane, click Autonomy Center.
On the Autonomy Center page, select a time range and find the Auto-Scaling Events that occurred within the selected time range.
Click Details to view the details of automatic space expansion.
