Configuring Auto Scaling Policies

Scenarios

You can configure auto scaling policies for your pay-per-use and yearly/monthly DB instances on the Basic Information page. When configuring auto scaling policies, you can enable or disable Auto Scale-up or Auto Scale-down. The scaling types include changing instance specifications and the number of read replicas.

Constraints

• Configuring auto scaling requires the iam:agencies:listAgencies permission.
• Changing DB instance specifications will briefly interrupt services.
• If you want to set Scaling Type to Number of read replicas, there must be only one proxy instance. For details, see Creating a Proxy Instance.
• The system will delete or add read replicas. To prevent your services from being affected, you are advised not to use an IP address for read to connect to your applications.

Modifying Auto Scaling Policies

1. Log in to the management console.
2. Click in the upper left corner and select a region and project.
3. Click in the upper left corner of the page, choose Database > TaurusDB.
4. On the Instances page, click the instance name to go to the Basic Information page.
5. In the DB Instance Information area, click Modify next to Auto Scaling.

6. In the displayed dialog box, configure the required parameters.

   Table 1 Parameter configuration

   Parameter	Parameter description
   Auto Scale-up	You can enable or disable it as needed.
   Scaling Type	Instance specifications Number of read replicas NOTE: You can select one or more scaling types. The read replicas that are automatically added or deleted will be billed based on a pay-per-use basis. If you deselect Number of read replicas for Scaling Type, pay-per-use nodes created in the current instance will be automatically deleted. Exercise caution when performing this operation. The account balance must be sufficient, or scaling up the specifications or adding read replicas may fail. After Auto Scale-up is enabled, read replicas that are automatically added cannot be promoted to primary.
   Observation Period	When auto scale-up is enabled, the system periodically checks CPU usage. If the average CPU usage exceeds the preset limit within the observation period, the system upgrades the specifications or adds read replicas based on the read and write traffic. The system enters a silent period after each scale-up. The minimum observation period is 5 minutes.
   Average CPU Usage	Indicates threshold for triggering an auto scale-up. Allowed range: 50%–100%
   Max. Specifications	Indicates the maximum specifications after the final auto scale-up. The specifications can only be scaled up gradually and the system enters the silent period after each scale-up.
   Max. Read Replicas	Only one read replica can be added at a time.
   Replica Read Weight	If you have enabled read/write splitting, the new read replicas are automatically associated with the proxy instance.
   Auto Scale-down	You can enable or disable it as needed. NOTE: Once auto scale-down is enabled, if the system observes an average CPU usage of 99% drops below 30% within the observation period, it gradually restores the original configuration. The system enters a silent period after each scale-down.
   Silent Period	The silent period is the minimum interval between two changes (triggered automatically or manually), where no more changes can happen.

7. Click OK.

Viewing Change History

1. Log in to the management console.
2. Click in the upper left corner and select a region and project.
3. Click in the upper left corner of the page, choose Database > TaurusDB.
4. On the Instances page, click the instance name to go to the Basic Information page.
5. In the DB Instance Information area, click View Change History next to Auto Scaling.
6. In the displayed dialog box, view the change time, change type, status, original specifications, and new specifications.