Question

What is instance size and availability zone flexibility? How does instance size flexibility help in reducing bills? Please help.

Answer 1

Availability Zone and instance size flexibility are the functionality provided by AWS to make it easier for you to take advantage of the regional RI’s in a discounted rate. Availability Zone flexibility applies for your RI’s discounted rate to the usage in any Availability Zone in a particular region, while instance size flexibility applies to your RI’s discounted rate which imply the usage of any size within an instance family. For example, let’s say you own an m5.2x large Linux/Unix regional RI which has a default tenancy in US East (N.Virginia). Then this RI’s can be taken at a discounted rate can automatically apply for two m5.x large instances in us-east-1a or four m5.large instances in us-east-1b.