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

Answer 1

Here's a link to Amazon's documentation:

http://aws.amazon.com/ec2/reserved-instances/#2

It doesn't explain/quantify what amount of usage constitutes Light, Medium, or Large but it gives a ballpark amount.

To summarize (excerpted from the above documentation):

• Light Utilization RIs are ideal for periodic workloads that only run a couple of hours a day, a few days per week, or very sporadically
• Medium Utilization RIs are best suited for workloads that run most of the time, but have some variability in usage (like web server traffic where demand may increase or decrease throughout the year)
• Heavy Utilization RIs offer the most absolute savings of any Reserved Instance type. They’re most appropriate for steady-state workloads where you’re willing to commit to always running these instances in exchange for our lowest hourly usage fee

If you're like me and wanted to see what we're getting for the prices we're paying for Light, Medium, and Heavy, here it is.

Answer 2

I think the answers are already great here. Just a tip that may help you to select the right reservation type is http://www.cloudorado.com/ . Go to advanced mode and then select how long you plan to run service (subscription duration) and how long the server will run per day. The service will choose the best reservation option - you can see it in details.

Answer 3

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.

Answer 4

The math here gets a little complicated. But, at the end of the day, it comes down to how many hours you'll be running instances for the reservation type/size/region that you have. It's gotten even more complicated now that you can trade in reservations for different AZ's and sizes.

There's a great blog series on choosing Reserved Instance types/quantities on the Cloudability blog.

http://cldy.co/choosing-ri-types

There's also a webinar recording that covers all the math:

http://cldy.co/ri-webinar-recording

Full disclosure: I work for Cloudability.

Answer 5

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.