Database Autonomy Service (DAS) allows you to specify a storage space threshold for a database instance. When the storage space reaches the specified threshold, the storage space of the database instance is insufficient. In this case, automatic space expansion is implemented to ensure that data can be written to the database as expected. This prevents data loss and the impact on business caused due to database instance breakdown. 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:
Database instance
Region
ApsaraDB RDS for MySQL Basic Edition instance that uses standard SSDs or Enterprise SSDs (ESSDs), 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 YiTian ApsaraDB RDS for MySQL instances that are formerly known as cost-effective ApsaraDB RDS for MySQL instances.
The automatic space expansion feature depends on the anomaly detection feature. You can enable automatic space expansion only for database instances in regions that support the anomaly detection feature. The anomaly detection feature is supported in the following regions:
China (Hangzhou), China (Shanghai), China (Shenzhen), China (Heyuan), China (Guangzhou), China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Nanjing - Local Region), China (Fuzhou - Local Region), China (Chengdu), China (Zhengzhou - Local Region), China (Hong Kong), Japan (Tokyo), South Korea (Seoul), Singapore, Malaysia (Kuala Lumpur), Indonesia (Jakarta), Philippines (Manila), Thailand (Bangkok), Australia (Sydney), UAE (Dubai), SAU (Riyadh - Partner Region), Germany (Frankfurt), US (Silicon Valley), US (Virginia), and UK (London)
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
NoteRead-only instances of ApsaraDB RDS for SQL Server do not support the automatic space expansion feature.
China (Hangzhou), China (Shanghai), China (Shenzhen), China (Heyuan), China (Qingdao), China (Beijing), China (Zhangjiakou), China (Hohhot), China (Ulanqab), China (Chengdu), China (Hong Kong), Japan (Tokyo), Singapore, Malaysia (Kuala Lumpur), Indonesia (Jakarta), Australia (Sydney), UAE (Dubai), Germany (Frankfurt), US (Silicon Valley), US (Virginia), and UK (London)
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 expanded storage space of the primary instance, 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.
In the upper-right corner of the Autonomy Center page, click Autonomy Service Settings.
On the Autonomous Function Settings tab of the panel, turn on the switch to enable 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 storage expansion.
If the available storage space of your database instance is less than or equal to the specified storage space threshold, the system automatically expands the storage space by increasing the following size of space, whichever is larger:
5 GB
NoteIf the total storage space of the database instance is less than 50 GB and the available storage space is less than 10% of the total storage space, the step size for storage space expansion is adjusted to 10 GB.
15% of the total storage space of the database instance. The result is the nearest integer that is a multiple of 5.
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 of the database instance after storage space expansion. The value of this parameter must be greater than or equal to the total 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.
In the left-side navigation pane of the page that appears, click Autonomy Center.
On the Autonomy Center page, select a time range to view the Auto-Scaling Events that occurred within the selected 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 scaled in. However, you can manually scale in the storage space by changing the instance specifications. For more information, see Change instance specifications.
NoteYou cannot manually scale in the storage space of ApsaraDB RDS for SQL Server instances.
You can enable the automatic fragment recycling 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 of a database instance.
For more information about how to expand the storage space of an ApsaraDB RDS for PostgreSQL instance, see Automatic storage expansion.