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I would like to know the best solution.

I have an instance of t3.medium type running 6 hours a day. Does it make sense for me to buy t3.nano type reserved instance, if so, how many instances? Or does it not pay to buy a reserved instance?

Leandro Pedrosa Rodrigues
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2 Answers2

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From a purely mathematical viewpoint, in US regions a t3.medium Linux instance would cost:

  • On-Demand: $0.0416 per Hour x 6 hours per day x 5 days per week x 52 weeks = $64.896 per year (Or ~$90 if 7 days per week)
  • 1-Year upfront Reserved instance: $213 per year
  • 3-Year upfront Reserved instance: $412 = $137 per year

So, the cheapest option is On-Demand.

An alternative is a Scheduled Reserved Instance, which "are a good choice for workloads that do not run continuously, but do run on a regular schedule." However, it seems that this option has been removed from the Management Console in some regions.

A Reserved Instance also includes a capacity reservation in case of capacity constraints, which makes it attractive beyond merely price.

John Rotenstein
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The maximum discount you can get is ~62% for 3 year, 100% upfront. Since you running the instance for only 6 hours / day, it makes no financial sense to reserve your instance.

helloV
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