Managing Read-Only Instance

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Managing Read-Only Instance

Last updated: 2024-12-31 17:33:00

Serverless clusters support mounting read-only instances to enhance read performance and concurrency while reducing the load on the read-write instance. This document describes how to create a read-only instance and modify its configuration for a serverless cluster.
Billing Description
The read-only and read-write instances have the same billing logic. For more information, see Billing Overview.
Creating Read-Only Instance
Note:
Read-only instance on the current version only supports vertical scaling but not horizontal scaling.
After purchasing a read-only instance group, you can adjust its compute unit and quantity.
The computing power of read-write instances or read-only instances has no impact on each other.
Read-only instances can only be automatically enabled and disabled, and a single instance can't be enabled or disabled manually.
Creating a read-only instance when purchasing a cluster
1. Log in to the TDSQL-C for MySQL console﻿
2. Behind the Serverless Architecture, select the Cluster Edition.
3. Beneath the Read-Only Group, select the number of read-only nodes within the group. You can add a maximum of fifteen read-only nodes.
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4. The configured compute unit range only takes effect for all the read-only nodes in the read-only group.
5. After configuring other configuration items for the serverless clusters, click Buy Now. For more information on the other configuration description of the serverless clusters, see Creating Serverless Cluster.
Adding Read-Only Instances to Existing Serverless Clusters
Note：
You can only perform the operations on the cluster in the running status.
1. Log in to the TDSQL-C for MySQL console, and select a region at the top.
2. Click Target Cluster in the cluster list on the left to enter the cluster management page.
3. Within the Cluster Management page, click on the "+" icon located in the read-only instance area of the topology diagram, or click on Serverless Configuration at the top right corner.
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4. Behind the Serverless Architecture, select the Cluster Edition.
5. Depending on the requirements, the number of read-only nodes within a read-only group can be increased, with a maximum of 15 read-only nodes allowable.
6. Configure the computational power range for the read-only group, which will be effective for all read-only nodes in the group.
7. Click Buy Now to add a read-only instance.
Modifying the ‌configuration of the read-only instance
You can adjust the number of the read-only instances and the compute unit range of the read-only group.
Note：
The cluster must be in a running state; configuration changes for read-only instances cannot be made while it is in a paused state.
After adjusting the number of read-only instances, you can manually trigger a load balancing to balance traffic.
You can adjust the number of the read-only instances on the configuration modification page. But you can't add or delete a read-only instance manually.
After a downgrade, the removed read-only instances will not be isolated in the Recycle Bin but will be eliminated directly. If you need to add read-only instances, please do so by adjusting the configuration to create read-only instances.
When the database proxy is enabled, the business will not be interrupted during the configuration modification.
1. Log in to the TDSQL-C for MySQL console, and select a region at the top.
2. Click the target cluster in the cluster list on the left to enter the cluster management page.
3. Within the Cluster Management page, click on the "+" icon located in the read-only instance area of the topology diagram, or click on Serverless Configuration at the top right corner.
4. In the pop-up window, simply select the desired number of read-only nodes and the computational power range to complete the configuration changes for the read-only instance.
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