AWS Certified Solutions Architect Professional SAP-C02 Practice Question

The correct answer is to use AWS Compute Optimizer. This service uses machine learning to analyze configuration and utilization metrics from CloudWatch to provide rightsizing recommendations for EC2 instances, Auto Scaling groups, and EBS volumes. It is specifically designed to identify under-provisioned and over-provisioned resources and recommends optimal instance types and sizes, including options from different instance families, to balance cost and performance. This is the most operationally efficient method for a large fleet as it automates the analysis.

Manually analyzing CloudWatch metrics is a valid but highly inefficient approach for a large fleet of instances. It requires significant manual effort to collect data, analyze it, and determine appropriate instance sizes, making it prone to error and time-consuming.

Using AWS Trusted Advisor is a good option for identifying underutilized instances. However, its 'Low Utilization Amazon EC2 Instances' check is based on simpler thresholds (e.g., CPU utilization below 10% for a number of days) and does not provide the same depth of analysis or the variety of recommendations (like cross-family suggestions) that AWS Compute Optimizer offers. Compute Optimizer is a more advanced and purpose-built tool for detailed rightsizing analysis.

Analyzing the AWS Cost and Usage Report (CUR) is not the best approach for this specific task. The CUR provides comprehensive cost and usage data but lacks the detailed performance metrics like CPU and memory utilization needed to make informed rightsizing decisions. While useful for cost allocation and tracking, it is not a performance analysis tool.