This topic describes how to create an RDS for 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 for 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

  1. Log on to the RDS console.
  2. Select the target region.选择地域
  3. Find the target instance and click its ID.
  4. Click Add Read-only Instance.添加只读实例
  5. On the purchase page, select the instance configuration and click Buy Now.购买界面
    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.
  6. 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

To view a read-only instance in the instance list, follow these steps:
  1. Log on to the RDS console.
  2. Select the target region.选择地域
  3. In the instance list, find the read-only instance and click its ID.选择只读实例

To view a read-only instance on the Basic Information page of the master instance, follow these steps:

  1. Log on to the RDS console.
  2. Select the target region.选择地域
  3. Find the master instance and click its ID.
  4. 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.主实例内跳转只读实例

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.

只读实例延迟

APIs

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