Configure automatic storage scaling

Considerations

• Use the WAL Log Management feature to check for redundant replication slots. You can manually delete inactive replication slots, which allows the ApsaraDB RDS for PostgreSQL kernel to automatically clear WAL logs. Then, check whether the storage space meets your business requirements. If it is still insufficient, configure automatic storage scaling.

• The automatic storage scaling rules for instances in each region have been gradually improved since February 28, 2023. When automatic storage scaling is triggered on a primary instance with read-only instances, the system checks the storage of each read-only instance. If a read-only instance has less storage than the primary's target capacity, it is scaled out first. The primary instance is scaled out only after all applicable read-only instances are scaled out. For more information, see [Product/Feature Change] Optimization of Automatic Storage Scaling Rules for ApsaraDB RDS for MySQL and ApsaraDB RDS for PostgreSQL Instances.

• If a backup is running on the instance, the automatic storage scaling task starts after the backup completes.

Billing

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

Procedure

1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.

2. In the Instance Resources section, click Settings to the right of Automatic Storage Expansion.

3. Configure the following parameters.

   Parameter	Description
   Automatic Storage Expansion	Enables or disables automatic storage scaling.
   Available Storage <=	Automatic scaling is triggered when the percentage of available storage falls to or below this value. Note The amount of storage added is the larger of the following two values: 5 GB. This amount increases to 10 GB if the instance's total storage is less than 50 GB and its available storage is less than 10%. 15% of the current storage capacity of the instance (rounded to the nearest multiple of 5).
   Maximum Storage Capacity	The upper limit for automatic storage scaling. This value must be greater than or equal to the current storage capacity of the instance. Maximum capacity for enterprise SSD (ESSD): 32,000 GB Maximum capacity for SSD cloud disk: 6,000 GB

4. Click OK.

View scaling history

1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.

2. In the Instance Resources section, click Storage Expansion Records to the right of Automatic Storage Expansion, which redirects you to the Database Autonomy Service (DAS) console.

3. On the Autonomy Center page, set Type to Auto Scaling Events to view the storage scaling history.

4. Click Details for a target auto scaling event. The event's details page displays basic information, such as the event severity and duration. On the Suggestions tab, the Problem and Suggestion section displays disk space usage and scaling recommendations; the Storage Suggestion section displays the original and recommended storage capacities (for example, an increase from 20 GB to 25 GB); and the Execution Details section displays the execution status and details for each step, such as Call RDS OpenAPI and Control Specification Change.

FAQ

Q: After automatic storage scaling is triggered, how long does the scaling process usually take to complete?

A: The time required for scaling cannot be accurately predicted as it depends on multiple factors, such as instance workload and data volume. You can go to the Task Hub to view the task progress.

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