Help Center > > User Guide> Working with RDS for MySQL> Instance Modifications> Changing a DB Instance Class

Changing a DB Instance Class

Updated at: May 14, 2021 GMT+08:00

Scenarios

You can change the instance class (CPU or memory) of a DB instance as required. If the status of a DB instance changes from Changing instance class to Available, the change is successful.

Only MySQL DB instances billed on the pay-per-use basis support scheduled instance class changes

Constraints

  • A DB instance cannot be deleted when its instance class is being changed.
  • DB instance classes can be scaled up or down, but the exclusive instance classes of DB instances using local SSDs can be scaled up only.
  • After you change instance classes, the DB instances will be rebooted and service will be interrupted. Therefore, you are advised to change instance classes during off-peak hours.

Procedure

  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click in the upper left corner of the page and choose Database > Relational Database Service. The RDS console is displayed.
  4. On the Instance Management page, locate the target DB instance and choose More > Change Instance Class in the Operation column.

    Alternatively, click the target DB instance to go to the Basic Information page. In the DB Information area, click Change in the Instance Class field.

  5. On the displayed page, specify the new instance class and click Next.

    Figure 1 Changing a DB instance class

    You can change the DB instance class as required.

    Changing the DB instance class will cause the DB instance to reboot. Select off-peak hours to avoid service interruptions.

    If you have selected In maintenance window for Scheduled Time, the DB instances will be rebooted during the instance class change time and services will be interrupted. To prevent service interruptions, you are advised to set the maintenance window to off-peak hours. For details, see Changing the Maintenance Window.

    DB instances in a DeC only support the general-enhanced instance classes.

  6. Confirm the specifications.

    • If you need to modify your settings, click Previous.
    • For pay-per-use DB instances, click Submit.

      To view the cost incurred by the DB instance class change, choose Billing Center > My Orders in the upper right corner.

    • For yearly/monthly DB instances:
      • If you intend to scale down the DB instance class, click Submit.

        The refund is automatically returned to your account. You can choose Billing Center > My Orders in the upper right corner to check the refund.

      • If you intend to scale up the DB instance class, click Pay Now. The scaling starts only after the payment is successful.

  7. View the DB instance class change result.

    • Changing the DB instance class takes 5–15 minutes. During this period, the status of the DB instance on the Instance Management page is Changing instance class. After a few minutes, click the DB instance and view the instance class on the displayed Basic Information page to check that the change is successful.
    • If you have selected Upon submission for Scheduled Time, return to the Instance Management page and view the DB instance status. During the change period, the instance is Changing instance class. After a few minutes, click the DB instance and view the instance class on the displayed Basic Information page to check that the change is successful.
    • If you have selected In maintenance window for Scheduled Time, return to the Instance Management page and choose Task Center in the navigation pane on the left. On the Scheduled Tasks page, view the execution progress and result of the task.

    After you change a MySQL instance class, the values of the following parameters will also be changed accordingly: back_log, innodb_buffer_pool_size, innodb_log_buffer_size, innodb_log_files_in_group, max_connections, innodb_page_cleaners, innodb_buffer_pool_instances, threadpool_size, and slave_parallel_workers.

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