Add a read-only replica to an instance

This topic describes how to add a read-only replica to an instance.

Procedure

1. Log in to the OceanBase Cloud console.

2. In the left-side navigation pane, click Instances.

3. In the instance list, find the target instance, and choose ··· > Manage Read-only Replicas in the Actions column.

4. In the Manage Read-Only Replicas dialog box, select the type of replica that you want to add.

   • Add a read-only replica: A read-only replica is suitable for scenarios where read isolation is required without affecting the read and write services of the instance. When you add a read-only replica, a replica is created only in one zone. We recommend that you use the same specification as the original one. After data synchronization is completed in the tenant settings, the read-only replica can be used normally.

   • Add a read-only columnstore replica: Data in a table on a read-only columnstore replica is stored in columnar format. OBServer automatically converts the storage format of data. This improves query and analysis performance in HTAP and OLAP scenarios. After you create a read-only columnstore replica for the instance, you must go to the tenant management page to create a read-only columnstore replica for the tenant, create a read-only endpoint to query the read-only columnstore replica, and then execute the SQL statements for data analysis.

   Note

   To use the read-only columnstore replica feature, contact OceanBase Technical Support to upgrade the database proxy (ODP) to V4.3.2 or later.

5. Click OK. You will be directed to the payment page. Configure the Node and Read-Only Replica Storage Capacity parameters as needed, select the Service Agreement option, and click Buy Now.

   Parameter	Description
   Zone	The zone in which the read-only replica is located.
   Read-only Replica Specification	The size of the read-only replica can be customized. The unit price is the same as that of the instance.
   Number of Read-only Replicas	The number of nodes that the read-only replica uses. Before you set the number of nodes and node specifications, note the following: All node specifications of the read-only replicas in a zone must be the same, while the specifications of read-only nodes of different read-only replicas can be different. For ease of management, we recommend that you use the same node specifications for read-only replicas in all zones as those of the instance. The number of nodes in a read-only replica in a zone cannot exceed the node number of the instance in the same zone. For example, if the node distribution of the instance is 2-2-2, the maximum number of nodes that can be created for a read-only replica in each zone is 2. For the selection of read-only replica node specifications, if its instance version is V4.x, the minimum node specification supports 4 cores. If its instance version is V3.x, the minimum node specification supports 8 cores.
   Storage	The storage size of the read-only replica, in GiB. Note The storage capacity constraints of a read-only replica are the same as those of the instance to which it belongs.