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

• You can change the DB instance class only when your account balance is greater than or equal to $0 USD.
• An instance cannot be deleted while its instance class is being changed.
• If the underlying ECS uses an architecture different from that of the target instance class, the instance class cannot be changed and a message will be displayed, indicating that instance class changes between the QingTian architecture and non-QingTian architecture are not allowed. For details about how to change ECS specifications, see General Operations.
• The dedicated instance class cannot be changed to any other instance class. For example, a general-purpose instance can be changed to a dedicated instance, but a dedicated instance cannot be changed to a general-purpose instance.
• To change the storage type to Extreme SSD V2, contact customer service.
• You can scale up or down the compute and memory capacity of RDS for SQL Server DB instances as needed.
• Only the instance classes of pay-per-use DB instances can be changed automatically during the maintenance window. To use this function, contact customer service.
• If you have selected Maintenance Window for Scheduled Time, the DB instance will be rebooted during the instance class change time and services will be interrupted. You are advised to set the maintenance window to off-peak hours.

• 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.

Instance Class or Storage Type Change

• You can change a general-purpose instance to a dedicated instance, but a dedicated instance cannot be changed to a general-purpose instance.
• You can change the storage type of an instance:
  • From high I/O to ultra-high I/O or cloud SSD.
  • From ultra-high I/O to extreme SSD or extreme SSD V2.
  • From cloud SSD to extreme SSD or extreme SSD V2.
  • From extreme SSD to extreme SSD V2.
  • To use the extreme SSD V2 storage type, contact customer service to apply for it.

Procedure

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

   Alternatively, click the instance name to go to the Overview page. Under Instance Class, click Configure.

5. On the displayed page, specify the new instance class and click Next.
   Figure 1 Changing a DB instance class
   

   To change the storage type to Extreme SSD V2, contact customer service. If the storage type is changed to Extreme SSD V2, you need to configure the IOPS. IOPS is separately billed on a pay-per-use basis.

   If you select Maintenance Window for Scheduled Time, the DB instance will be rebooted during the instance class change time and services will be interrupted. You are advised to set the maintenance window to off-peak hours.

   DB instances in a DCC only support the general-enhanced instance class.

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 & Costs > Bills 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 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.

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 Instances page is Changing instance class. After a few minutes, click the instance name and view the instance class displayed on the Overview page to check that the change is successful.

   

   After you change the instance class of an RDS for SQL Server instance, the value of max server memory will be changed accordingly. You are advised to set max server memory to Memory size (GB) x 1024 x 0.85 – 1.5 x 1024. For example, if your memory is 4 GB, set max server memory to 1946 MB (4 x 1024 x 0.85-1.5 x 1024).