Chapter 3. Setting persistent kernel tuning parameters

download PDF

When you have decided on a tuning configuration that works for your system, you can make the changes persistent across reboots.

By default, edited kernel tuning parameters only remain in effect until the system reboots or the parameters are explicitly changed. This is effective for establishing the initial tuning configuration. It also provides a safety mechanism. If the edited parameters cause the machine to behave erratically, rebooting the machine returns the parameters to the previous configuration.

3.1. Making persistent kernel tuning parameter changes

You can make persistent changes to kernel tuning parameters by adding the parameter to the /etc/sysctl.conf file.


This procedure does not change any of the kernel tuning parameters in the current session. The changes entered into /etc/sysctl.conf only affect future sessions.


  • You have root permissions on the system.


  1. Open /etc/sysctl.conf in a text editor.
  2. Insert the new entry into the file with the parameter’s value.

    Modify the parameter name by removing the /proc/sys/ path, changing the remaining slash (/) to a period (.), and including the parameter’s value.

    For example, to make the command echo 0 > /proc/sys/kernel/hung_task_panic persistent, enter the following into /etc/sysctl.conf:

    # Enable gettimeofday(2)
    kernel.hung_task_panic = 0
  3. Save and close the file.
  4. Reboot the system for changes to take effect.


  • To verify the configuration:

    # cat /proc/sys/kernel/hung_task_panic
Red Hat logoGithubRedditYoutubeTwitter


Try, buy, & sell


About Red Hat Documentation

We help Red Hat users innovate and achieve their goals with our products and services with content they can trust.

Making open source more inclusive

Red Hat is committed to replacing problematic language in our code, documentation, and web properties. For more details, see the Red Hat Blog.

About Red Hat

We deliver hardened solutions that make it easier for enterprises to work across platforms and environments, from the core datacenter to the network edge.

© 2024 Red Hat, Inc.