ConfigureShard - Amazon ElastiCache
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Node group (shard) configuration options when adding or removing replicas. Each node group (shard) configuration has the following members: NodeGroupId, NewReplicaCount, and PreferredAvailabilityZones.



In the following list, the required parameters are described first.


The number of replicas you want in this node group at the end of this operation. The maximum value for NewReplicaCount is 5. The minimum value depends upon the type of Redis replication group you are working with.

The minimum number of replicas in a shard or replication group is:

  • Redis (cluster mode disabled)

    • If Multi-AZ: 1

    • If Multi-AZ: 0

  • Redis (cluster mode enabled): 0 (though you will not be able to failover to a replica if your primary node fails)

Type: Integer

Required: Yes


The 4-digit id for the node group you are configuring. For Redis (cluster mode disabled) replication groups, the node group id is always 0001. To find a Redis (cluster mode enabled)'s node group's (shard's) id, see Finding a Shard's Id.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 4.

Pattern: \d+

Required: Yes


A list of PreferredAvailabilityZone strings that specify which availability zones the replication group's nodes are to be in. The nummber of PreferredAvailabilityZone values must equal the value of NewReplicaCount plus 1 to account for the primary node. If this member of ReplicaConfiguration is omitted, ElastiCache for Redis selects the availability zone for each of the replicas.

Type: Array of strings

Required: No


The outpost ARNs in which the cache cluster is created.

Type: Array of strings

Required: No

See Also

For more information about using this API in one of the language-specific Amazon SDKs, see the following: