To Serve Web Traffic for a Popular Product Your Chief

question 361

Multiple Choice

To serve Web traffic for a popular product your chief financial officer and IT director have purchased 10 m1.large heavy utilization Reserved Instances (RIs) , evenly spread across two availability zones; Route 53 is used to deliver the traffic to an Elastic Load Balancer (ELB) . After several months, the product grows even more popular and you need additional capacity. As a result, your company purchases two C3.2xlarge medium utilization Ris. You register the two c3.2xlarge instances with your ELB and quickly find that the m1.large instances are at 100% of capacity and the c3.2xlarge instances have significant capacity that's unused. Which option is the most cost effective and uses EC2 capacity most effectively?

• A) Configure Autoscaling group and Launch Configuration with ELB to add up to 10 more on-demand m1.large instances when triggered by Cloudwatch. Shut off c3.2xlarge instances.
• B) Configure ELB with two c3.2xlarge instances and use on-demand Autoscaling group for up to two additional c3.2xlarge instances. Shut off m1.large instances.
• C) Route traffic to EC2 m1.large and c3.2xlarge instances directly using Route 53 latency based routing and health checks. Shut off ELB.
• D) Use a separate ELB for each instance type and distribute load to ELBs with Route 53 weighted round robin.

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Definitions:

Utility Theory

A theory in economics that assesses the usefulness or satisfaction a consumer gains from consuming goods and services.

Total Utility

The complete fulfillment experienced from the consumption of a specific amount of products or services.

Marginal Utility

The increased happiness or value a buyer experiences by consuming an extra unit of a good or service.

Diminishing Marginal Utility

The principle that as an individual consumes more of a good, the utility (satisfaction or benefit) gained from each additional unit decreases.