Add one or more read-only instances to your dedicated cluster to offload read traffic from the primary instance, improving read performance and increasing application throughput.
Prerequisites
Before you begin, ensure that you have:
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A primary ApsaraDB MyBase for MySQL instance. For more information, see Create an ApsaraDB MyBase for MySQL instance
Background information
For more information about ApsaraDB for MyBase, see What is ApsaraDB for MyBase?
Limits
| Edition | Maximum read-only instances per primary instance |
|---|---|
| Master-replica Edition | 5 |
| High-availability Edition | 7 |
To increase the quota, submit a ticket.
Usage notes
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Updating the minor engine version of the primary instance also updates the minor engine versions of all associated read-only instances. For more information, see Update the minor engine version of an ApsaraDB RDS for MySQL instance.
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Modifying the configurations of a primary instance restarts all associated read-only instances.
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When a primary instance is released upon expiration, all associated read-only instances are automatically released.
Create a read-only instance
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Log on to the ApsaraDB for MyBase console.
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In the upper-left corner of the page, select a region.
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In the left-side navigation pane, click Clusters. Find the dedicated cluster and click Details in the Actions column.
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Open the creation dialog using one of the following methods:
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Method 1 (all editions): Find the instance, and choose More > Create Read-only Instance in the Actions column.
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Method 2 (Master-replica Edition only): Find the instance and click Details in the Actions column. In the left-side navigation pane, click Service Availability, then click Add Node.
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Configure the following parameters.
Parameter Description Read-only Instance Switchable Specifies whether the read-only instance can be promoted to a primary instance. Available only for primary instances using Master-replica Edition. At least one read-only instance must have this option enabled. Instance Type Select the specifications for the read-only instance. Storage Capacity Set the storage capacity for the read-only instance. The value must be greater than or equal to the storage capacity of the primary instance. Deployment Method Select Default Policy or Specified Host. VPC Select the virtual private cloud (VPC) to which the host belongs. vSwitch Select the vSwitch for the read-only instance. To view vSwitch details, go to the VPC console. -
Click OK.
What's next
After the read-only instance is created, direct read traffic to it using one of the following approaches:
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Update your application endpoint: Modify your application code to send read requests to the read-only instance endpoint.
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Enable read/write splitting: Use the Database Proxy terminal to automatically route write requests to the primary instance and distribute read requests across read-only instances by weight. For more information, see Create a Database Proxy terminal for an ApsaraDB MyBase for MySQL instance.