Discrepancies Between VM CPU Usage % in Aria Operations and Linux Guest OS

Products

• VCF Operations/Automation (formerly VMware Aria Suite)

Issue/Introduction

• Users may notice discrepancies between the VM CPU Usage % value shown in VMware Aria Operations and the CPU Usage % displayed in the Linux Guest OS
• This article explains the cause of these differences and provides clarity on how Aria Operations calculates CPU metrics

Environment

• Aria Operations 8.x

Cause

• The observed discrepancy between the VM CPU Usage % displayed in Aria Operations and the value shown in the Linux Guest OS is due to the different data collection methods employed by each tool
• Due to differences in calculation methodologies, the values in Aria Operations may not match those displayed in the Guest OS

Resolution

 

• Understanding the Discrepancy:
  
  • The CPU Usage % value in Aria Operations is derived using the following formula:
    
    • CPU Usage (%) = CPU|Usage (MHz) / CPU|Total Capacity (MHz) * 100

 

• Verification of Metric Values:
  
  • Check the current values of the metrics in Aria Operations from the Metrics tab of the respective VM:
    
    • CPU|Usage (MHz): 3211.93 MHz
    • CPU|Total Capacity (MHz): 33519.23 MHz

 

• Calculation Example:
  
  • Using the formula above:
    
    • 3211.93 / 33519.23 * 100 = 9.582%

 

• Comparison of Results:
  
  • The calculated value of 9.582% closely matches the current VM CPU Usage % value displayed in Aria Operations, which is 9.579%.

 

• Conclusion:
  
  • These differences are expected due to the distinct methodologies of Guest OS and Aria Operations in calculating CPU usage metrics.

Additional Information

• The difference between CPU Usage % values in Aria Operations and the Guest OS is normal and does not indicate a problem