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Amazon ElastiCache
User Guide (API Version 2015-02-02)

Creating a Redis Cluster with Replicas

You have the following options for creating a cluster with replica nodes. Which you use depends on whether you already have an available Redis (cluster mode disabled) cluster not associated with any cluster that has replicas to use as the primary node, or you need to create the primary node in with the cluster, and read replicas. Currently, a Redis (cluster mode enabled) cluster must be created from scratch.

Option 1: Creating a Cluster with Replicas Using an Available Redis (cluster mode disabled) Cluster

Use this option to leverage an existing single-node Redis (cluster mode disabled) cluster. You will specify this cluster as the primary in the new cluster, and then individually add 1 to 5 read replica to the cluster. If the existing cluster is active, read replicas synchronize with it as they are created.

Important

You cannot create a Redis (cluster mode enabled) cluster using an existing cluster. To create a Redis (cluster mode enabled) cluster (API/CLI: replication group) using the ElastiCache console, see Creating a Redis (cluster mode enabled) Cluster (Console).

Option 2: Creating a Redis Cluster with Replicas from Scratch

Use this option if you don't already have an available Redis (cluster mode disabled) cluster to use as the cluster's primary, or if you want to create a Redis (cluster mode enabled) cluster. If you're creating a Redis (cluster mode disabled) cluster, using this option you specify how many read replicas you want. If you're creating a Redis (cluster mode enabled) cluster, using this option you specify both the number of shards and replicas per shard you want. The process then creates the cluster, shards, primary node and the specified number of read replicas without further input or actions from you.