Automatic performance scaling

Process of automatic scale-up

Pricing

• For an ApsaraDB RDS for MySQL instance:

  You are charged based on the new instance specifications after the automatic scale-up. The price for a scale-up varies based on the instance configurations, such as the region and the new instance specifications. For more information, visit the ApsaraDB RDS buy page.

• For a PolarDB for MySQL cluster:

  For information about the pricing rules, see Configuration change fees.

Scenarios

After you enable the automatic performance scaling feature for a database instance, DAS automatically scales up the database instance during peak hours. This can double the read/write throughput and lower the CPU utilization from higher than 90% to 25%. The database instance can run under a heavy load for approximately 10 hours. After the traffic decreases and the CPU utilization drops to lower than 25%, DAS sends messages to suggest you to scale down the database instance to the original specifications.

This way, DAS can manage your database instance to handle traffic spikes during peak hours and help ensure the stability of your business.

Impacts

• When your database instance is being scaled up or scaled down, a transient connection that lasts approximately 30 seconds may occur. Make sure that your application is configured to automatically reconnect to the database instance.
• If the database engine of the database instance is not of the latest version, DAS updates the database instance to run the database engine of the latest version when DAS scales up the database instance. This ensures the performance and stability of your database instance.

Procedure

1. Log on to the DAS console.
2. In the left-side navigation pane, click Instance Monitoring.
3. On the page that appears, find the database instance that you want to manage and click the instance ID. The instance details page appears.
4. In the left-side navigation pane, click Autonomy Center.
5. In the upper-right corner of the Autonomy Center page, click Autonomy Service Settings.
   
6. On the Autonomous Function Settings tab of the Autonomous Function Management panel, enable the autonomy service. Then, configure the following parameters on the Optimization and Throttling tab.
   • For an ApsaraDB RDS for MySQL instance, select Automatic Performance Scaling and configure the following parameters.

     Parameter	Description
     Average CPU Utilization	The threshold based on which automatic scale-up is triggered. If the average CPU utilization is greater than or equal to the specified threshold, automatic scale-up is triggered.
     Observation Window	The time range during which you want to observe the performance of the database instance. DAS checks the CPU utilization of the database instance during an observation window at specific intervals. If the CPU utilization reaches the value of the Average CPU Utilization parameter, automatic scale-up is triggered.
     Maximum Specifications	The maximum specifications to which you can upgrade the database instance. If the CPU utilization of the database instance reaches the value of Average CPU Utilization, DAS scales up the instance. If the CPU utilization of the database instance reaches the value of Average CPU Utilization again during the next observation window, DAS scales up the database instance again. This process is repeated until the database instance is scaled up to the maximum specifications that you specified.

   • For a PolarDB for MySQL cluster, select Automatic Scale-up/out and Automatic Scale-down/in and configure the following parameters.

     Parameter	Description
     Average CPU Utilization	The threshold based on which automatic scale-up is triggered. If the average CPU utilization is greater than or equal to the specified threshold, automatic scale-up is triggered.
     Maximum Specifications	The maximum specifications to which you can upgrade the database instance. After automatic scale-up is triggered, the system scales up your PolarDB cluster to the maximum specifications in small increments. For example, the CPU specification can be upgraded from 4 cores to 8 cores, and then to 16 cores until the upper limit is reached.
     Maximum Number of Read-only Nodes	The maximum number of read-only nodes that the cluster can contain. After automatic scale-up is triggered, read-only nodes are automatically added to the PolarDB cluster one by one until the upper limit is reached. Note The nodes that are automatically added are associated with the default endpoint of your cluster. If you use a custom endpoint, you must specify whether these nodes are automatically associated with the endpoint by using the Automatically Associate New Nodes parameter. For more information about how to configure Automatically Associate New Nodes, see Configure PolarProxy.
     Observation Window	If the average CPU utilization reaches or exceeds the specified threshold during the observation window, PolarDB automatically scales out or scales up the cluster after the observation window ends. This ensures that the cluster can handle all read and write requests. For example, if the length of the observation window is 5 minutes and the time required to complete a scaling activity is 10 minutes, you must wait 15 minutes before you can check the scaling result.
     Quiescent Period	The minimum interval between two automatic scale-up operations or two automatic scale-down operations. During a quiescent period, PolarDB continuously tracks whether the trigger conditions for an automatic scale-up or scale-down operation are met. During this period, automatic scale-up or scale-down is not triggered. If a quiescent period and an observation window end at the same time and the CPU utilization reaches the threshold within the observation window, PolarDB triggers automatic scale-out.

7. Click OK.

Best practices