Disabling scale-in activity

You can prevent the target-tracking scaling policy configuration from scaling in your cluster by disabling scale-in activity. Disabling scale-in activity prevents the scaling policy from deleting shards, while still allowing the scaling policy to create them as needed.

You can specify a Boolean value for DisableScaleIn to enable or disable scale in activity for your cluster. For more information, see TargetTrackingScalingPolicyConfiguration in the Application Auto Scaling API Reference.

The following example describes a target-tracking configuration for a scaling policy. In this configuration, the ElastiCachePrimaryEngineCPUUtilization predefined metric adjusts an ElastiCache for Valkey and Redis OSS cluster based on an average CPU utilization of 40 percent across all primary nodes in that cluster. The configuration disables scale-in activity for the scaling policy.

{
    "TargetValue": 40.0,
    "PredefinedMetricSpecification":
    {
        "PredefinedMetricType": "ElastiCachePrimaryEngineCPUUtilization"
    },
    "DisableScaleIn": true
}