CDM cpu_status and cpu_history callbacks don't work for 5 minutes on AIX

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

The article explains the behaviour of the CDM probe on AIX system.

You may notice that CDM cpu_status and cpu_history callbacks don't work for 5 minutes after a restart on AIX.
 
This does not happen in Windows. 
 

Environment

DX UIM 20.4.x / 23.4.x

CDM probe

Resolution

When the CDM probe starts on an AIX machine, it collects CPU and memory metrics using system commands—sar for CPU and vmstat for memory. These commands are executed based on the interval configured in the probe settings (The interval that is set in the probe is passed as an argument directly to these commands)

The probe is designed to provide an accurate picture of the system's performance. To do this, it calculates the average CPU and memory usage over a set time period, rather than just taking a single, instantaneous reading, which could be misleading (e.g., a temporary spike at startup).

The CPU and memory information is only available after the first 5-minute (interval period) collection cycle is complete. For history data, which needs at least two data points to show a trend, the user may have to wait for the second 5-minute cycle to finish, which is why it can take up to 10 minutes for all data to appear.

As a result, callbacks such as cpu_status, cpu_history, and memory_history may not return complete or accurate data immediately after the probe starts or restarts. The system needs time to gather enough samples to calculate a reliable average.