This document delineates the process of creating read-only instances/nodes with provisioned resources for clusters characterized by provisioned resource configurations, through the TDSQL-C for MySQL console.
TDSQL-C for MySQL allows you to create one or more read-only instances in a cluster, which are suitable for read/write separation and one-write-multiple-read application scenarios and can greatly enhance the read load capacity of your database cluster.
A TDSQL-C for MySQL cluster supports two instance types: Read-write instances and read-only instances. Among them, based on the different mode of instance, read-only instances are categorized into provisioned resource read-only instances and Serverless read-only instances.
A TDSQL-C for MySQL cluster provides private read-write and read-only addresses by default. You can access all read-only instances at the cluster's private read-only address. After a read-only instance is created, access requests to it at the private read-only address will be automatically forwarded to it.
A read-only instance is billed in the same way as the read-write instance. For more information, see Product Pricing.
Read-only and read-write instances share the same storage, so there is no need to maintain the account and database.
A read-only instance does not need to replicate or migrate data, nor does it need to be synced with a read-write instance through binlog. It can be created in seconds.
The delay between a read-only instance and the read-write instance is usually within milliseconds, which can be viewed through the read-only instance delay monitoring metric on the monitoring and alarms page.
Read-only and read-write instances can have different specifications. However, to make it easier for you to adjust the configuration based on the load, we recommend that you keep the specifications of read-only instances the same.
When you add a yearly/monthly subscribed read-only instance to a yearly/monthly subscribed cluster, the instance will expire at the same time as the cluster.
Directions
On the cluster list page, proceed based on the actually used view mode.
Tab view
List view
1. Log in to the TDSQL-C for MySQL console, and click the target cluster in the cluster list on the left to enter the cluster management page.
2. Under Cluster Details, click "+" on the read-only instance section of the topology diagram, or click Add Now under the read-only instance information on the right.
3. On the purchase page, select the target read-only instance configuration, confirm that everything is correct, and click Buy Now. Then, you can view the new instance in the instance list.
1. Log in to the TDSQL-C for MySQL console and click a cluster ID/name in the cluster list or Manage in the Operation column to enter the cluster management page.
2. On the cluster management page, select the Instance List tab and click Read-Only Instance > Add Read-Only Instance to enter the read-only instance purchase page.
3. On the purchase page, select the target read-only instance configuration, confirm that everything is correct, and click Buy Now. Then, you can view the new instance in the instance list.
