Instance Size Flexibility for AWS RDS Reserved Instances

Question

EC2 RI is working based on normalization factor and Instance Size Flexibility with the same family.

Let’s say you already own an RI for a c4.8xlarge. This RI now applies to any usage of a Linux/UNIX C4 instance with shared tenancy in the region. This could be:

• One c4.8xlarge instance.
• Two c4.4xlarge instances.
• Four c4.2xlarge instances.
• Sixteen c4.large instances.

Same thing applied to AWS RDS RI? As I have researched on AWS documentation and another website that provides AWS tool but not getting any comment regarding this.

• AWS Blog: New – Instance Size Flexibility for EC2 Reserved Instances
• What's New: Amazon EC2 Reserved Instances now offer instance size flexibility, helping you reduce your EC2 bill

In the same example, if I have RDS RI t2.xLarge can it cover my two t2.large on my AWS account?

Answer 1

Instance Size flexibility applies only to Amazon EC2.

It does not apply to Amazon RDS reserved instances.

Even though Amazon RDS runs on top of Amazon EC2 technology, they are not quite the same as Amazon EC2 instances themselves. For example, they are shown in the RDS console, but not the EC2 console.