You can manually add or remove read-only nodes after you create a PolarDB cluster.
Background information
A PolarDB cluster can contain up to 15 read-only nodes. Each cluster must have at least one read-only node to ensure high availability. All nodes in a cluster have the same specifications.
Billing methods of nodes
You are charged for newly added nodes based on the following billing methods:
- If nodes are added to a subscription cluster, you are charged based on the subscription billing method.
- If nodes are added to a pay-as-you-go cluster, you are charged on an hourly basis.
Note
- You can release subscription or pay-as-you-go read-only nodes at any time. After you release the nodes, the system refunds fees for the remaining subscription period or stops billing. For more information, see Configuration change fees.
- Only the node specifications of the added nodes are charged. For more information, see Specifications and pricing. The storage fee is charged based on the amount of the used storage, regardless of the number of nodes.
Precautions
- You can add or remove read-only nodes only when the cluster does not have pending configuration changes.
- To avoid misoperations, only one read-only node can be added or removed at a time. To add or remove multiple read-only nodes, repeat the operation for multiple times.
- It takes about five minutes to add or remove a node.
Add a read-only node
Remove a read-only node
Related API operations
API | Description |
---|---|
CreateDBNodes | Adds nodes to a specified PolarDB cluster. |
ModifyDBNodeClass | Changes the specifications of nodes in a specified PolarDB cluster. |
RestartDBNode | Restarts a specified node in a PolarDB cluster. |
DeleteDBNodes | Removes a specified node from a PolarDB cluster. |