The automatic scale-up feature of Database Autonomy Service (DAS) can automatically scale up your ApsaraDB RDS for MySQL instance based on your workloads to handle traffic spikes and ensure the stability of your business. This topic describes how to enable automatic scale-up.

Prerequisites

  • Your RDS instance runs RDS High-availability Edition with standard SSDs or enhanced SSDs (ESSDs).
  • DAS is activated for your Alibaba Cloud account. For more information, see Autonomy center.

Billing

The automatic scale-up feature is free of charge. You are charged only for the scale-ups that are triggered. For more information, see Specification change fees.

Automatic scale-up process

Flowchart

After you enable automatic scale-up and the average CPU utilization of your RDS instance over a specific time range reaches the specified threshold, DAS automatically scales up your RDS instance based on the workloads that are run on your RDS instance. The specifications after a scale-up cannot exceed the specifications that are indicated by the Upper Limit of Specifications parameter in the ApsaraDB RDS console. After your RDS instance is scaled up, DAS continues to monitor the CPU utilization of your RDS instance. If the CPU utilization reaches the specified threshold again, DAS scales up your RDS instance again. This process continues until the specifications of your RDS instance reach the maximum specifications that you specify.

Note
  • After automatic scale-up is enabled, ApsaraDB RDS assigns the AliyunServiceRoleForDAS service-linked role to DAS. This way, DAS can access resources related to ApsaraDB RDS.
  • After your RDS instance is scaled up, it cannot be automatically scaled down. You can subscribe to scale-down suggestions and manually change the specifications of your RDS instance based on the suggestions. For more information, see Event subscription and Change the specifications of an ApsaraDB RDS for MySQL instance.
  • If the average CPU utilization of your RDS instance is lower than 30% over the time range that is specified by the Observation Window parameter in the ApsaraDB RDS console, the system pushes scale-down suggestions. The default value of the Observation Window parameter is 30 minutes.

Impacts

  • When the new specifications are being applied, you may encounter a transient connection of about 30 seconds. Make sure that your application is configured to automatically reconnect to your RDS instance.
  • If you are not using the latest minor engine version, DAS updates the minor engine version of your RDS instance to the latest version when DAS scales up your RDS instance. This ensures the performance and stability of your database service.

Procedure

  1. Visit the RDS instance list, select a region above, and click the target instance ID.
  2. In the Configuration Information section, click Settings to the right of Automatic Scale-up.
  3. In the dialog box that appears, configure the following parameters.
    Parameter Description
    Automatic Scale-up Specify whether to enable automatic scale-up.
    Observation Window Select the time range during which you want to observe the performance of your RDS instance. Valid values:
    • 20 minutes
    • 30 minutes
    • 40 minutes
    • 60 minutes
    Note DAS periodically checks the CPU utilization of your RDS instance during the selected time range. If the CPU utilization reaches the value of Average CPU Utilization, an automatic scale-up is triggered.
    Average CPU Utilization Specify the average CPU utilization threshold based on which DAS scales up your RDS instance. Unit: percent (%). Valid values: 50 to 90. The threshold can be adjusted at a step size of 10%.
    Upper Limit of Specifications Select the maximum specifications based on which DAS scales up your RDS instance.
    Note If the CPU utilization of your RDS instance reaches the value of Average CPU Utilization, DAS scales up your RDS instance based on your business requirements. If the CPU utilization of your RDS instance reaches the value of the Average CPU Utilization parameter again during the time range that is specified by Observation Window, DAS scales up your RDS instance again. This process continues until the specifications of your RDS instance reach the maximum specifications that you specify.
  4. Click OK.
    In the Configuration Information section, the status of Automatic Scale-up changes to Enabled.