Add a read replica to a cluster

Prerequisites

The read replica feature is currently in the beta testing phase and is available only to whitelisted users. If you want to use this feature, contact OceanBase technical support.

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 More in the rightmost column.

4. Click Manage Read Replicas.

5. In the Manage Read Replicas dialog box, select the type of replica to add and select a zone.

   • Add Read Replica: Read replicas are suitable for scenarios where you need to isolate read-only requests without affecting the cluster's read/write services. A new read replica is created in a single zone. We recommend that you keep its specifications consistent with the original specifications. After the replica is created, you must configure data synchronization in the tenant settings to start using it.

   • Add Read-only Column-store Replica: In a read-only column-store replica, data tables are stored in a columnar format. The OceanBase kernel automatically transforms the data storage format. This can significantly improve query analysis performance in hybrid transactional and analytical processing (HTAP) and online analytical processing (OLAP) scenarios. After you create a read-only column-store replica for the cluster, you must also create one for the tenant on the tenant management page. Then, create a read-only endpoint to query the replica and execute SQL statements for data analytics.

     Note

     To use the read-only column-store replica feature, contact OceanBase technical support to upgrade your database proxy (ODP) to V4.3.2 or later.

6. Click OK. The system redirects you to the payment page.

7. Set Nodes and Read Replica Storage Size as needed. Then, check Terms of Service and click Buy Now.

   Parameter	Description
   Nodes	Includes node specifications and the number of nodes. Click to add a node and select the node specifications from the drop-down list. Before you set the number of nodes and node specifications, note the following: In a single zone, all nodes of a read replica must have the same specifications. However, different read replicas can have different node specifications. For easier management, we recommend that you keep the node specifications of read replicas in all zones consistent with the cluster specifications. The node specifications of all read replicas must be smaller than the specifications of a single node in the cluster instance. The number of read replica nodes in a single zone cannot exceed the number of cluster nodes in a single zone. For example, if Node Distribution is 2-2-2 on the Cluster Instance Workbench, you can create a maximum of two read replica nodes in each zone. When you select node specifications for a read replica, if the cluster instance is V4.x, the minimum specification for a node is 4 cores. If the cluster instance is V3.x, the minimum specification for a node is 8 cores.
   Read Replica Storage Size	The storage size of the read replica in GB. Note The minimum value for Read Replica Storage Size cannot be smaller than the minimum storage size allowed by the current specifications. The maximum value cannot exceed the storage size of the cluster instance.