If the storage space of a database instance is insufficient, data may fail to be written to the database. As a result, data loss occurs or even the database instance breaks down, which seriously affects service operations. Database Autonomy Service (DAS) supports automatic space expansion when the storage space reaches the threshold that you specify. During the expansion, you do not need to restart the database instance, and your services are not affected.
Prerequisites
The database instance that you want to manage is of one of the following types:
ApsaraDB RDS for MySQL Basic Edition instance that uses standard SSDs or enhanced SSDs (ESSDs), High-availability Edition instance that uses standard SSDs or ESSDs, or Cluster Edition instance that uses standard SSDs or ESSDs
ApsaraDB MyBase for MySQL High-availability Edition instance that uses standard SSDs or ESSDs
ApsaraDB RDS for SQL Server High-availability Edition instance that uses standard SSDs or ESSDs or Cluster Edition instance that uses standard SSDs or ESSDs
NoteDAS does not support the automatic space expansion feature for cost-effective ApsaraDB RDS for MySQL instances that originally use the ARM architecture.
Read-only instances of ApsaraDB RDS for SQL Server do not support the automatic space expansion feature.
The balance of your Alibaba Cloud account is sufficient to pay for the resources that are required to expand storage space.
The service-linked role for DAS is created. For more information, see AliyunServiceRoleForDAS role.
NoteIf no service-linked role is created for DAS, the system automatically creates the 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 the storage space to which that 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 specific ApsaraDB RDS for SQL Server instances due to the limits 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.
Billing
The billing rules for automatic space expansion are the same as those for manual space 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 of the page that appears, 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 automatic space expansion feature.
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 storage expansion.
If the available storage space of your database instance is less than or equal to the storage space threshold that is specified by the Available Storage Space parameter, the system automatically expands the storage by increasing the following size of space, whichever is larger:
5 GB
15% of the storage space of the instance
For example, if the total storage space of a database instance is 100 GB, the storage space is increased by 15 GB when the storage space threshold is reached. After the expansion, the total storage space of the database instance is 115 GB.
Maximum Storage of Automatic Expansion
The maximum storage space allowed for the database instance after the automatic space expansion. The value of this parameter must be greater than or equal to the storage space of the database instance.
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.
On the instance details page, click Autonomy Center in the left-side navigation pane.
On the Autonomy Center page, specify a time range and view the Auto-Scaling Events that occurred within the specified time range.
Click Details to view the details of automatic space expansion.
References
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.
You can enable the automatic fragment reclamation feature to clear tablespace fragments and reduce storage space wastes. For more information, see Automatic tablespace fragment recycling.
You can use the storage analysis and capacity assessment features to view and analyze the storage usage. For more information, see Storage analysis and Capacity assessment.
For more information about how to expand the storage space of an ApsaraDB RDS for PostgreSQL instance, see Automatic storage expansion.