Master Linux Stress Testing with stress‑ng: Install, Commands & Real‑World Scenarios

Stress‑ng Tool Overview

stress‑ng is a powerful Linux stress‑testing utility that can generate load on various system resources such as CPU, disk, network, memory, processes, and file systems. It extends the original stress tool with many more stressors and supports fine‑grained control of test intensity and duration.

Installation

1. yum installation (quick but may not be the latest version)

yum install -y epel-release.noarch && yum -y update

yum install -y stress stress-ng

2. Source installation (recommended for the newest release)

Download the latest source package, extract it, compile and install:

wget https://fossies.org/linux/privat/stress-ng-0.16.03.tar.gz

tar -xzf stress-ng-0.16.03.tar.gz

cd stress-ng-0.16.03

make && make install

After a successful build, verify the installation:

stress-ng -V

Command Usage and Common Options

stress-ng [OPTION [ARG]]

Key options include:

-h, --help            Show help information
--version             Show version information
-t, --timeout SECS   Run for the specified number of seconds
-c, --cpu N           Spawn N workers that repeatedly call sqrt() to stress CPU
-i, --io N            Spawn N workers that repeatedly call sync() to stress I/O
-m, --vm N            Spawn N workers that allocate/free memory to stress RAM
-d, --hdd N           Spawn N workers that perform write/unlink operations
--cpu-method METHOD   Choose a specific CPU stress method
--metrics             Output execution metrics
--vm-bytes BYTES      Size of each memory allocation (default 256M)
--class CLASS         Select a class of stressors
--matrix MODE         Enable matrix test mode
--random-seed SEED    Set random seed for reproducibility
--sequential          Enable sequential test mode
--hdd-bytes BYTES     Amount of data each HDD worker writes
--cpu-load PERCENT    Target CPU load percentage

Practical Stress‑Testing Scenarios

1. CPU Load Test

Run four CPU workers using the matrix multiplication stressor for 600 seconds:

stress-ng --cpu 4 --cpu-method matrixprod --timeout 600s

Monitor the system before and during the test with top (screenshots omitted for brevity).

2. Memory Load Test

Allocate 512 MiB in each of four workers, keep the allocation for 600 seconds: stress-ng --vm 4 --vm-bytes 512M --timeout 600s Check memory usage with free and top before and during the test.

3. I/O Load Test

Spawn four I/O workers for a 600‑second test: stress-ng --io 4 --timeout 600s Observe disk activity using top and a Prometheus monitoring setup.

4. Disk Write Test

Use one HDD worker to write 1000 MiB blocks with four I/O workers for 600 seconds:

stress-ng --io 4 --hdd 1 --hdd-bytes 1000M --timeout 600s

5. Combined CPU and I/O Test

Run four CPU workers and two I/O workers simultaneously for 600 seconds:

stress-ng --cpu 4 -i 2 --timeout 600s

6. Adjusted CPU Load Percentage

Test four CPU workers with a target load of 60 % for 600 seconds: stress-ng --cpu 4 --cpu-load 60 --timeout 600s During all scenarios, use top (or Prometheus) to capture real‑time load metrics and verify that the intended stress level is achieved.

Conclusion

stress‑ng provides a rich set of options for generating realistic load on Linux systems. By selecting appropriate stressors and parameters, you can simulate CPU, memory, I/O, and disk pressure, monitor the impact with standard tools, and fine‑tune the intensity to match testing requirements.