This topic describes how to create an RDS PPAS read-only instance. You can create read-only instances to process massive read requests sent to the database and increase the application throughput. A read-only instance is a read-only copy of the master instance. Changes to the master instance are also automatically synchronized to all relevant read-only instances.
For more information, see Introduction to PPAS read-only instances.
Prerequisites
- The master instance is an RDS PPAS 10.0 instance.
- The configuration of the master instance must be at least 8-core 32 GB (dedicated or dedicated-host instance).
Precautions
- You can create read-only instances under a master instance but cannot switch an existing instance to a read-only instance.
- Creating a read-only instance does not affect the master instance because the read-only instance copies data from the slave instance.
- Read-only instances do not inherit parameter settings of the master instance, but use default parameter settings. You can modify the parameter settings on the console.
- Specifications and storage capacity of each read-only instance cannot be lower than those of the master instance.
- Each master instance can have up to five read-only instances.
- A read-only instance is charged according to the Pay-As-You-Go billing method. That is, fees are deducted for a read-only instance once every hour.
Create a read-only instance
- Log on to the RDS console.
- Select the target region.
- Find the target instance and click its ID.
- Click Add Read-only Instance.
- On the purchase page, select the instance configuration and click Buy Now.Note
- We recommend that you deploy read-only instances and the master instance in the same VPC.
- The configuration (memory and storage) of each read-only instance must be equal to or higher than that of the master instance.
- You can deploy up to five read-only instances to improve availability and horizontally scale performance.
- On the Order Confirmation page, review the order information, select Terms of Service, Service Level Agreement, and Terms of Use, click Pay Now, and complete the payment.
The instance creation takes a few minutes.
View a read-only instance
- Log on to the RDS console.
- Select the target region.
- In the instance list, find the read-only instance and click its ID.
To view a read-only instance on the Basic Information page of the master instance, follow these steps:
- Log on to the RDS console.
- Select the target region.
- Find the master instance and click its ID.
- On the Basic Information page of the master instance, move the pointer over the number below Read-only Instance and click the ID of the read-only instance.
View the delay of a read-only instance
When a read-only instance synchronizes data from the master instance, the read-only instance may lag behind the master instance by a small amount of time. You can view the delay on the Basic Information page of the read-only instance.

APIs
API | Description |
---|---|
CreateReadOnlyDBInstance | Used to create an RDS read-only instance. |