A company needs to host a web server on Amazon EC2 instances for at least 1 year. The web server cannot tolerate interruption. Which EC2 instance purchasing option will meet these requirements MOST co

Question

Options

• AOn-Demand Instances
• BPartial Upfront Reserved Instances
• CSpot Instances
• DNo Upfront Reserved Instances

• A
  9% (3)
• B
  84% (27)
• C
  3% (1)
• D
  3% (1)

Explanation

Explanation

Partial Upfront Reserved Instances offer the best balance of cost savings and reliability for a known, long-term workload - providing up to ~40-60% savings compared to On-Demand pricing by committing to a 1 or 3-year term, while guaranteeing capacity without interruption risk.

Why the distractors are wrong:

• On-Demand Instances (A) are the most expensive option for sustained, predictable workloads since you pay the full hourly rate with no discount for commitment.
• Spot Instances (C) are the cheapest option overall but can be interrupted with only 2 minutes' notice - directly violating the "cannot tolerate interruption" requirement.
• No Upfront Reserved Instances (D) also provide Reserved Instance discounts, but because you pay nothing upfront, the monthly cost is slightly higher than Partial Upfront, making it less cost-effective over the full year.

Memory Tip: Think of it as a sliding scale - more upfront = more savings. Since the question asks for most cost-effective without requiring all upfront (which isn't listed), Partial Upfront is the sweet spot. Whenever you see "long-term + no interruption," immediately eliminate Spot Instances and lean toward Reserved Instances.

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