Question #831
A company operates a critical web service hosted on Amazon EC2 instances. The service must maintain continuous availability as it handles a steadily increasing number of user requests projected to grow over several years. Which EC2 instance purchasing model provides the MOST cost-effective solution while ensuring uninterrupted operation?
Spot Instances
On-Demand Instances
Savings Plans
Dedicated Hosts
Explanation
The correct answer is C (Savings Plans) because:
1. Cost-Effectiveness: Savings Plans provide up to 72% discounts compared to On-Demand pricing when committing to consistent usage over 1-3 years, ideal for steadily growing workloads.
2. Uninterrupted Operation: Unlike Spot Instances (A), Savings Plans guarantee capacity without interruptions, critical for the service's availability.
3. Long-Term Scalability: Savings Plans automatically apply discounts to any instance family/size in a region, accommodating growth better than rigid Dedicated Hosts (D) or expensive On-Demand (B).
Why Others Are Incorrect:
- A (Spot): Risk of termination makes it unsuitable for critical services.
- B (On-Demand): No discounts for long-term use, leading to higher costs.
- D (Dedicated Hosts): Higher costs unless specific licensing needs exist; no inherent scalability benefits.
Key Points: Savings Plans balance cost savings with reliability for predictable, long-term workloads.
Answer
The correct answer is: C