How to Optimize a 24/7 EC2 Workload with Reserved Instances?
A company runs an uninterruptible Amazon EC2 workload on AWS 24 hours a day, 7 days a week. The company will require the same instance family and instance type to run the workload for the next 12 months. Which combination of purchasing options should the company choose to MOST optimize costs? (Choose two.)
Community Votes
100% of anonymous learners picked answer AE. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
The exam tests matching steady-state EC2 usage to the deepest-discount commitment; the trap is picking Convertible RIs or Compute Savings Plans for flexibility the workload does not need.
For a 24/7 EC2 workload that will keep the same instance family and type for 12 months, a Standard Reserved Instance purchased All Upfront delivers the deepest discount. This page confirms the correct CLF-C02 pairing and explains why flexible alternatives cost more.
Many learners choose Convertible Reserved Instance or Compute Savings Plan because they sound more flexible, but flexibility reduces the discount when the family and type are already fixed.
Community Discussion (5 comments)
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Expert Analysis
Why the Answer Is Correct
A Standard Reserved Instance is designed for predictable, steady-state EC2 usage where the instance family and instance type are known in advance, exactly matching the company’s 12-month requirement. Because the workload runs 24/7 and cannot be interrupted, the Standard RI term commitment produces a much lower effective hourly cost than On-Demand or Spot. The All Upfront payment option then maximizes the Reserved Instance discount by paying the full term cost at purchase. Together, A and E form the deepest-discount combination for this fixed EC2 workload.Why the Other Options Are Wrong
A Convertible Reserved Instance offers exchange flexibility but generally provides a smaller discount than a Standard RI, so it is not the most cost-optimal choice when the instance family and type are already fixed. A Compute Savings Plan is broader and flexible across EC2 families and other compute services, but that flexibility comes with a lower discount rate than a Standard RI for this specific steady-state workload. Spot Instances can be reclaimed by AWS with little notice, which directly conflicts with the stated uninterruptible workload. All Upfront is not a standalone instance purchasing model; it is the payment schedule that makes the Standard RI option cheaper.Community Comment Notes
One learner, 4336e3d, correctly connected Standard RIs to predictable 24/7 usage and All Upfront payment to the maximum discount. Nikmah summarized the Reserved Instance commitment terms, including one- or three-year terms and All, Partial, or No Upfront payment, which supports choosing E. JoeTromundo’s comment “COMBINATION!” highlights that the question asks for two paired choices rather than a single purchasing model, and CCNP21 also concluded A and E. The community consensus aligns with the exam doctrine here, but the deciding factor remains the fixed instance family, fixed type, and full 12-month term.Official Reference
Exam Strategy
When a scenario fixes instance family, instance type, and a full term, eliminate Spot first and favor Standard RIs over flexible commitments. Then choose All Upfront if cash flow allows because it maximizes the Reserved Instance discount.
Frequently Asked Questions
Why isn't a Compute Savings Plan the best fit for this fixed EC2 workload?
Compute Savings Plans are flexible across EC2 families and other compute, but that flexibility yields a smaller discount than a Standard RI when the family and type are already known for 12 months.
Does All Upfront payment change which Reserved Instance type to buy?
No; All Upfront is a payment option applied to the RI. Standard RI plus All Upfront is the deepest-discount combination for this predictable workload.
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