Exam: AWS Certified Cloud Practitioner 0 Likes
The application experiences a predictable amount of usage, including (CLF-C02)
A user is comparing purchase options for an application that runs on Amazon EC2 and Amazon RDS. The application cannot sustain any interruption. The application experiences a predictable amount of usage, including some seasonal spikes that last only a few weeks at a time. It is not possible to modify the application.
Which purchase option meets these requirements MOST cost-effectively?
A) Review the AWS Marketplace and buy Partial Upfront Reserved Instances to cover the predicted and seasonal load.
B) Buy Reserved Instances for the predicted amount of usage throughout the year. Allow any seasonal usage to run on Spot Instances.
C) Buy Reserved Instances for the predicted amount of usage throughout the year. Allow any seasonal usage to run at an On-Demand rate.
D) Buy Reserved Instances to cover all potential usage that results from the seasonal usage.
Solution
Correct answer: C) Buy Reserved Instances for the predicted amount of usage throughout the year. Allow any seasonal usage to run at an On-Demand rate.
Option C is likely the most cost-effective choice for the described scenario:
Buying Reserved Instances (RIs) for the predicted amount of usage throughout the year allows you to benefit from cost savings compared to On-Demand pricing. RIs provide a discounted rate in exchange for a commitment to a one- or three-year term.
Allowing seasonal usage to run at an On-Demand rate ensures that you only pay for the additional capacity during the spikes without committing to Reserved Instances for the unpredictable, short-duration spikes.
Options A, B, and D have certain drawbacks:
Option A (Review the AWS Marketplace and buy Partial Upfront Reserved Instances) may not be the most cost-effective as Partial Upfront Reserved Instances require an upfront payment, and the utilization patterns described may not fit well with this model.
Option B (Buy Reserved Instances for the predicted amount of usage throughout the year. Allow any seasonal usage to run on Spot Instances) introduces Spot Instances for seasonal spikes, but Spot Instances can be terminated with little notice, which may not be suitable for an application that cannot sustain any interruption.
Option D (Buy Reserved Instances to cover all potential usage that results from the seasonal usage) might result in overcommitting and paying for capacity that is not consistently used throughout the year, potentially leading to higher costs.
Category: Economic aspects of the AWS cloud