Add and remove nodes

Background information

OceanBase Database offers architectural advantages for elastic scaling compared to traditional databases, which typically store data on a single machine. By distributing data across multiple machines, OceanBase Database addresses the scalability challenges inherent in traditional architectures. If a cluster or tenant requires more capacity, you can add nodes. This allows the cluster to support more tenants and enables tenants to handle increased data and service traffic.

Usage notes

OceanBase Database lets you add or remove nodes from a cluster to scale the instance. For example, consider a cluster instance in a multi-zone deployment. This cluster has three zones, with one node in each zone (a 1-1-1 node distribution). When you add or remove nodes, the resources change as follows:

• Add nodes: You can increase the number of nodes in multiples of the number of zones. This action increases the instance's computing resources and storage space. For example, if you change the total number of nodes from 3 to 9, two nodes are added to each zone, resulting in a 3-3-3 node distribution.

• Remove nodes: You can only remove nodes from an instance if you have previously added nodes to it. Removing nodes reduces the instance's computing resources and storage space.

Prerequisites

Before you add or remove nodes, ensure that the following conditions are met:

• The cluster is in the Running state.

• All tenants in the cluster are in the Running state.

• The cluster is not in a temporary capacity state.

Procedure

1. Log on to the OceanBase Management Console .

2. In the navigation pane on the left, click Instance List.

3. In the instance list, find the target cluster instance and click its name to open the Cluster Instance Workspace.

4. In the upper-right corner, click the More icon and then click Standard Upgrade/Downgrade.

5. Click Add Node or Remove Node.

   1. You cannot add nodes if the database version is V4.1.x.

   2. You cannot remove nodes if the database version is between V4.0 and V4.2.

   3. The number of nodes cannot be greater than 120 or less than 3.

      Note

      To increase the number of nodes, contact OceanBase technical support.

   4. If the cluster has an endpoint in direct connection mode, adding nodes may cause applications to access resources across data centers, which increases latency. After the scale-out operation is complete, replace the endpoint in direct connection mode with the primary endpoint or another endpoint in your application.

6. Set the number of nodes and select the Terms of Service checkbox.

7. Click Purchase and complete the payment.

What to do next

After the scaling operation is complete, you can view the updated number of nodes in the Cluster Instance Workspace.