How to use the command 'nmon' (with examples)

The nmon command is a system administrator, tuner, and benchmark tool. It provides a detailed view of system performance by collecting and displaying real-time performance data. It is particularly useful for monitoring system resources and troubleshooting performance issues.

Use case 1: Start nmon

Code:

nmon

Motivation: Starting nmon without any arguments allows you to quickly launch the tool and monitor the system in real-time. This is helpful when you want to get an immediate snapshot of the system’s performance without specifying any specific options.

Explanation: In this use case, the nmon command is executed without any arguments. This will start nmon in interactive mode, displaying real-time performance data on the terminal screen.

Example output:

NMON (Ver1.0)    Do you want to start the recording now? Yes

Use case 2: Save records to file

Code:

nmon -f

Motivation: Saving records to file allows you to collect performance data over a specified period of time, which can be useful for analyzing system performance trends, generating reports, and troubleshooting intermittent issues.

Explanation: In this use case, the -f option is used to instruct nmon to save the collected performance data to a file. By default, nmon saves records every 300 seconds (5 minutes) for a total of 288 measurements.

Example output:

NMON (Ver1.0)    Saving data to file every 300 seconds (5 minutes) for a total of 288 measurements

Use case 3: Save records to file with customized intervals

Code:

nmon -f -s 30 -c 240

Motivation: Sometimes, you may want to collect performance data at shorter or longer intervals than the default frequency. Specifying custom intervals allows you to fine-tune the data collection process to better match your monitoring needs.

Explanation: In this use case, the -s and -c options are used to customize the interval and total number of measurements respectively. The -s 30 option instructs nmon to save records every 30 seconds, and the -c 240 option specifies a total of 240 measurements.

Example output:

NMON (Ver1.0)    Saving data to file every 30 seconds for a total of 240 measurements

Conclusion:

The nmon command is a versatile tool that provides valuable insights into system performance. By utilizing different options, you can start nmon in interactive mode, save records to file, and customize the intervals between measurements. This allows you to monitor and analyze your system’s performance efficiently and effectively, aiding in both troubleshooting and optimization efforts.