ElastiCache Reserved Node Recommendations – Support for Size Flexibility

CloudHealth is announcing support for generating size-flexible ElastiCache recommendations for the Redis, Valkey, and Memcached engine types. AWS introduced Size flexibility for ElastiCache reserved nodes in October 2024, Reserved cache nodes purchased with any size can potentially cover bigger or smaller-sized cache nodes within the same instance family for a given AWS Region and cache engine ( e.g customers with Redis OSS reserved nodes can apply this discount to the Valkey engine). Now you can change to different node sizes within the same node family while still retaining the reserved node discount. The discounts will be adjusted based on the normalization factor. For example, a reserved node for cache.r6g.xlarge can be applied to cache.r6g.2xlarge, but not to cache.r6gd.large, because cache.r6g and cache.r6gd belong to different node families.

To support size flexibility in ElastiCache RI, CloudHealth recommends the smallest instance type within the family, regardless which instance type is being used. Note that only one recommendation is made for each instance family.