Oversized instances within Auto Scaling Groups lead to inflated baseline costs, even when scaling adjusts the number of instances dynamically. When workloads consistently use only a fraction of the available CPU, memory, or network capacity, there is an opportunity to downsize to smaller, less expensive instance types without sacrificing performance. Right-sizing helps balance capacity and efficiency, reducing compute spend while preserving workload stability.

Detection:

• Identify Auto Scaling Groups where instances exhibit low average CPU, memory, or network utilization relative to their capacity.
• Review instance sizing in relation to historical workload peaks and scaling behavior.
• Assess whether smaller, more cost-effective instance types could support the same workload with acceptable performance.
• Evaluate launch configurations or templates to determine if default instance types were selected without performance optimization.
• Confirm with application and infrastructure owners that resizing aligns with performance, availability, and SLA requirements.