Help Center> Document Database Service> User Guide> Instance Modifications> Changing Replica Set Instance Nodes> Adding Replica Set Instance Nodes
Updated on 2023-12-13 GMT+08:00
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Adding Replica Set Instance Nodes

DDS allows you to scale out a three-node replica set instance to up to five or even seven nodes. All newly added nodes are secondary nodes and support primary/secondary switchovers, improving data reliability.

Only whitelisted users can use this function. You need to submit a service ticket to apply for this function. In the upper right corner of the management console, choose Service Tickets > Create Service Ticket to submit a service ticket.

Precautions

  • To add nodes, instance status must be Available, Deleting backup, or Checking restoration.
  • A DB instance cannot be deleted while nodes are being added.
  • If there are any newly added standby nodes, they will be unable to participate in this switchover. When you add a new standby node, the HA connection address needs to be reconfigured, and the new node is frozen for 12 hours.
  • When an instance node is being added, the DB instance may be intermittently disconnected once or twice for up to 30s each time.
  • Nodes cannot be manually deleted.

Pricing Details

  • A pay-per-use instance is still billed on an hourly basis after new nodes are added.
  • If you add nodes to a yearly/monthly instance, you will pay price difference or get a refund.
  • For details, see Product Pricing Details.

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 Databases > Document Database Service.
  4. On the Instances page, click the replica set instance name.
  5. In the Node Information area on the Basic Information page, click Change Secondary Nodes.

    Figure 1 Basic information

  6. Specify Total Nodes and click Next.

    Figure 2 Selecting the number of nodes

    You can add five or seven nodes.

  7. On the displayed page, confirm the node configuration information.

    • For yearly/monthly DB instances
      • If you need to modify your settings, click Previous to go back to the page for you to specify details.
      • If you do not need to modify your settings, click Submit to go to the payment page and complete the payment.
    • For pay-per-use DB instances
      • If you need to modify your settings, click Previous to go back to the page for you to specify details.
      • If you do not need to modify your settings, click Submit to add the nodes.

  8. View the result of adding nodes.

    • When a node is being added, the status of the instance is Adding node. The entire process takes about 15 minutes.
    • In the Node Information area, view the information about the nodes you added.
    Figure 3 Node information