What is the Difference between a Light, Medium or Heavy utilization Reserved instances on EC2?

Question

They talk about the different utilization instances, but I can't find a single place that actually states what the difference is between a light utilization Large instance or a heavy utilization Large instance other than price. Can someone please tell me what the difference is?

Answer 1

The instances are the same. It's just a pricing difference so you can save money if you know you will be using the instance a lot, by paying an upfront cost.

You pay more up front for a heavier utilization instance, but you save more in the long run assuming you have it running all the time, because the hourly rate is cheaper.

So it's just a matter of how much you will be using the instance (having it running) that determines which type is the best value for you. If it will be on all the time for a year or 3 years, then a heavy utilization is definitely the cheapest option.

Answer 2

on demand, light, medium, and heavy offer different up-front vs hourly costs, with progressively higher up-front costs, and lower per-hour costs..

according to http://aws.amazon.com/ec2/reserved-instances/

Light Utilization RIs – The break-even point for a Light Utilization Linux RI (vs. On-Demand Instances) is 28% for a 1-year term or 11% of a 3-year term. If you expect to use your instance more than that, an RI will save you money.

Medium Utilization RIs – The break-even point for a Medium Utilization Linux RI (vs. Light Utilization Reserved Instances) is 41% for a 1-year term or 19% of a 3-year term.

Heavy Utilization RIs – The break-even point for a Heavy Utilization Linux RIs (vs. Medium Utilization Reserved Instances) is 56% for a 1-year term or 35% of a 3-year term.