Changing a DB Instance Class

Scenarios

You can change the instance class (vCPU 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.

Constraints

• An instance cannot be deleted while its instance class is being changed.
• The following operations cannot be performed on an instance whose instance class is being changed: rebooting the instance, scaling up storage space, modifying the parameter template, creating a manual backup, creating a database account, and creating a database.
• After the instance class is changed, some parameters are automatically changed to the default values defined in the new instance class. The parameters are threadpool_size, innodb_buffer_pool_size, innodb_io_capacity, innodb_io_capacity_max, innodb_buffer_pool_instances, back_log, and max_connections.
• Changing an instance class will interrupt services. Ensure that your applications support automatic reconnection. Perform this operation during off-peak hours because changing an instance class during peak hours takes much more time.
• Changing an instance class takes 5 to 15 minutes.

Procedure

1. Log in to the management console.
2. Click in the upper left corner of the page and choose Databases > Relational Database Service.
3. On the Instances 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 next to the Instance Class field.

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

5. Confirm the specifications.
   • If you need to modify your settings, click Previous.
   • For pay-per-use DB instances, click Submit.
   • 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 click Billing in the upper right corner and then choose Orders > My Orders in the navigation pane on the left to view the details.

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

6. Check the change result.

   Return to the Instances page and view the instance status. During the change period, the instance status is Changing instance class. You can view the execution progress of Changing a MySQL DB instance class on the Task Center page. After a few minutes, view the DB instance class on the Basic Information page to check that the change is successful.

   

   After the instance class is changed, the values of the following parameters will 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.