Scale Read Throughput with Tair Read-Write Splitting - Tair

Read/write splitting offloads read traffic from the primary node to dedicated read replicas, which works best for workloads with a high read-to-write ratio.

Prerequisites

Before you begin, ensure that you have:

A cloud-native instance (convert a classic instance to cloud-native deployment mode first)
A supported instance type: Redis Open-Source Edition, or a DRAM-based or persistent memory-optimized Tair (Enterprise Edition) instance
An instance with 1 GB or more memory
A high-availability instance
For cluster instances: proxy mode connection

Before you enable

Transient disconnection: Enabling or disabling read/write splitting causes a brief connection interruption. Perform this operation during off-peak hours and implement auto-reconnection logic in your application.
Command restrictions: Some commands are not supported on read/write splitting instances. Review Limits on commands supported by cluster instances and read/write splitting instances before enabling.

Enable read/write splitting

Log on to the console and go to the Instances page. In the top navigation bar, select the region where your instance resides, then click the instance ID.
In the left navigation pane, click Node Management.
Turn on the Read/Write Splitting switch.
In the panel that appears, confirm the instance configuration and fees, then click Pay.
New read replicas have the same specifications as the primary node.
Follow the prompts to complete the payment.

After payment succeeds, the instance status changes to Changing Configuration. Wait 1–5 minutes for the status to change to Running. Track progress on the instance details page.

For instances deployed across multiple availability zones, the system provides separate endpoints for the primary zone and secondary zone. Both endpoints support read and write operations. To minimize latency and distribute load, route requests from the secondary zone to the secondary zone endpoint.

Modify or disable read/write splitting

On the Node Management page:

Modify the number of read replicas: Click Modify in the Actions column. Standard instances support 1–9 read replicas. Cluster instances support 1–4 read replicas per shard.
Disable read/write splitting: Turn off the Read/Write Splitting switch.

FAQ

Why do I get "The primary availability zone requires at least one read-only node" when enabling read/write splitting?

Your standard instance has only a primary node in the primary zone, with no replica nodes. Read/write splitting requires at least one replica node in the primary zone alongside the primary node.

To resolve this, add at least one replica node to your instance in the primary zone.

How long does it take for changes to take effect?

After payment succeeds, the instance status changes to Changing Configuration. Changes typically complete within 1–5 minutes, after which the status returns to Running.

How many read replicas can I add?

Standard instances: 1–9 read replicas
Cluster instances: 1–4 read replicas per shard

New read replicas have the same specifications as the primary node.