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

Dimensions for ElastiCache Metrics

All ElastiCache metrics use the AWS/ElastiCache namespace and provide metrics for a single dimension, the CacheNodeId, which is the automatically generated identifier for each cache node in the cache cluster. You can find out what these values are for your cache nodes by using the DescribeCacheClusters API or describe-cache-clusters command line utility. For more information, see DescribeCacheClusters in the Amazon ElastiCache API Reference and describe-cache-clusters in the AWS CLI Command Reference.

Each metric is published under a single set of dimensions. When retrieving metrics, you must supply both the CacheClusterId and CacheNodeId dimensions.