EC2 Instance Savings Plan VS Flexible reserved instance

Question

When we want to resize our compute instance and also want to change family and region in future which is best plan for minimal downtime when upgrading instance.

And also what is the difference between both of them. What is exactly meant by manual intervention if we consider convertible reserved instance in case resizing the instance compare to compute saving instance.

re:Post Agent · Answer

When considering the need for flexibility in resizing EC2 instances, changing instance families, and potentially moving across regions, the EC2 Instance Savings Plan and Flexible Reserved Instances (also known as Convertible Reserved Instances) offer different advantages. However, for your specific requirements, the Compute Savings Plan would be the best option.

Compute Savings Plans provide the most flexibility and are better suited for your needs. They allow you to:

1. Resize instances
        2. Change instance families
        3. Switch regions

All of these can be done without any manual intervention or downtime. Compute Savings Plans automatically apply to EC2 instance usage regardless of instance family, size, Availability Zone, region, operating system, or tenancy. This means you can freely move from one instance type to another, shift workloads between regions, or even transition between EC2, Fargate, and Lambda services while still benefiting from the discounted rates.

In contrast, EC2 Instance Savings Plans are tied to a specific instance family in a particular region. While they allow for changes in instance size, operating system, and tenancy within that family and region, they don't offer the cross-region or cross-family flexibility you're looking for.

Flexible Reserved Instances (Convertible RIs) do offer some flexibility to change instance family, size, OS, tenancy, and region. However, these changes require manual exchanges, which could potentially lead to some downtime or administrative overhead.

For minimal downtime and maximum flexibility when upgrading instances, changing families, or moving across regions, the Compute Savings Plan is the most suitable option. It provides up to 66% savings compared to On-Demand pricing while offering the adaptability you need for your dynamic infrastructure requirements.
      
**Sources**  
[Savings Plans - Amazon EC2 Reserved Instances and Other AWS Reservation Models](https://docs.aws.amazon.com/whitepapers/latest/cost-optimization-reservation-models/savings-plans.html)  
[Main Differences b/t EC2 Saving Plans (Compute and Instance) and Reserved Instances | AWS re:Post](https://repost.aws/questions/QUeethov1VSDm1QvziWqMHzw/main-differences-b-t-ec2-saving-plans-compute-and-instance-and-reserved-instances)  
[Pricing Of EC2 Instances: Saving Plan and Reserved Instances | AWS re:Post](https://repost.aws/questions/QUdZaXLUV6TIajScJexA0qJA/pricing-of-ec2-instances-saving-plan-and-reserved-instances)

EC2 Instance Savings Plan VS Flexible reserved instance

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