Most Cost-Effective RDS and EC2 Savings Strategy

SAA-C03 By islever Editorial Last updated

Design cost-optimized database solutions. Design cost-optimized compute solutions.

Short answer

D Purchase 3-year Reserved Instances and Savings Plans with All Upfront payments to secure the maximum possible discount for long-running RDS and EC2 workloads.

Question

A company is migrating its databases to Amazon RDS for PostgreSQL. The company is migrating its applications to Amazon EC2 instances. The company wants to optimize costs for long-running workloads. Which solution will meet this requirement MOST cost-effectively?
  1. Use On-Demand Instances for the Amazon RDS for PostgreSQL workloads. Purchase a 1 year Compute Savings Plan with the No Upfront option for the EC2 instances.
  2. Purchase Reserved Instances for a 1 year term with the No Upfront option for the Amazon RDS for PostgreSQL workloads. Purchase a 1 year EC2 Instance Savings Plan with the No Upfront option for the EC2 instances.
  3. Purchase Reserved Instances for a 1 year term with the Partial Upfront option for the Amazon RDS for PostgreSQL workloads. Purchase a 1 year EC2 Instance Savings Plan with the Partial Upfront option for the EC2 instances.
  4. Purchase Reserved Instances for a 3 year term with the All Upfront option for the Amazon RDS for PostgreSQL workloads. Purchase a 3 year EC2 Instance Savings Plan with the All Upfront option for the EC2 instances. Correct Answer

Key Takeaways

The exam tests the trade-off between upfront cash flow and total savings; the common trap is choosing flexibility (No Upfront) over maximum discount (All Upfront + 3 Year).

This question explores the most cost-effective way to optimize costs for long-running Amazon RDS and EC2 workloads using Reserved Instances and Savings Plans. The correct approach maximizes discounts by committing to a 3-year term with All Upfront payments.

Common mistake: Learners often choose Option B or C because they prefer the lower initial capital expenditure of No or Partial Upfront, failing to recognize that 'MOST cost-effectively' prioritizes lowest total price regardless of cash flow timing.

Expert Analysis

Why the Answer Is Correct

To meet the requirement of optimizing costs for long-running workloads MOST cost-effectively, you must minimize the total spend over the lifecycle. A 3-year Reserved Instance (RI) offers significantly deeper discounts than a 1-year RI. Furthermore, among payment options, All Upfront provides the highest discount percentage compared to Partial or No Upfront. Therefore, combining the longest term (3 years) with the highest discount tier (All Upfront) yields the absolute lowest cost.

Why the Other Options Are Wrong

Options A, B, and C all result in higher total costs. Option A uses On-Demand pricing for RDS, which is the most expensive option and should be avoided for stable workloads. Option B uses 1-year terms, which have smaller discounts than 3-year terms. Option C uses Partial Upfront, which saves less money than All Upfront. While these options preserve cash flow, they do not answer the specific constraint of being 'MOST cost-effective'.

Community Comment Notes

The community consensus strongly supports Option D. As user LeonSauveterre noted, 'All Upfront - Pay the full cost upfront... Lowest additional cost', highlighting the financial logic. User JunsK1e confirmed that 'D is the correct... It gives you big discount if you purchase with all upfront'. Multiple other users reinforced that longer reservations and upfront payments drive the deepest savings.

Exam Strategy

When AWS questions ask for the 'MOST cost-effective' solution for steady-state/long-running workloads, always look for the combination of the longest commitment period (3 years) and the highest discount payment option (All Upfront). Do not let concerns about cash flow distract you from the mathematical lowest price.

Frequently Asked Questions

Why not choose No Upfront for better cash flow?

No Upfront preserves cash but offers the smallest discount. Since the question asks for 'MOST cost-effective,' total price matters more than cash flow timing.

Is a Savings Plan better than Reserved Instances for EC2?

EC2 Instance Savings Plans offer similar discounts to RIs but provide flexibility across instance families. Both are valid cost-saving mechanisms when paired with All Upfront/Long Term.

More SAA-C03 FAQ →

Community Votes

D
100%

100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 6 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 6

  1. LeonSauveterre 👍 5 Answered D
    What you should know: 1. No Upfront - Pay nothing at the time of purchase. Payments are spread out monthly over the term (1 or 3 years). Lowest savings with high flexibility. 2. Partial Upfront - Pay a portion of the cost upfront, with reduced monthly payments over the term. Moderate savings with moderate flexibility. 3. All Upfront - Pay the full cost upfront at the time of purchase. No additional payments required during the term. Highest savings with the least flexibility. Merely by the question, option D would be the answer because it's best for companies with a stable workload, long-term commitment, and sufficient budget for upfront payments. Just to add something, generally option C would be the best in real world cases because it strikes a good balance between savings and upfront investment, and uitable for mid-term commitments with moderate budget flexibility.
  2. JunsK1e 👍 3 Answered D
    letter D is the correct, It gives you big discount if you purchase with all upfront
  3. 744fdad 👍 2
    the longer the reservation the more the savings too for reserved
  4. nebajp 👍 1 Answered D
    Correct Answer - D, All upfront is cheaper than partial and no upfront.
  5. swati1508 👍 2
    D is correct
Show 1 more comment
  1. muhammadahmer36 👍 1 Answered D
    D is right

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