Skip to main content

Kernel Tuneable's

vmlinuz-5.15.0-106-generic

Note; is the kernel is prefaced with vmlinuz - this means that the kernel is compressed and must be uncompressed on boot. If the kernel file is prefaced with vmlinux - then it isn't compressed.

Working on Linux systems, you may see systems with various kernels installed.

To check which kernel is currently being treated as the primary one (which will be loaded on boot), you can check the symlinks (in /boot), as below:

vmlinuz -> vmlinuz-5.15.0-107-generic

vmlinuz.old -> vmlinuz-5.15.0-106-generic



Kernel Tunables

In Linux, a tunable refers to a specific type of configuration setting within the kernel. These tunables allow you to customize the behavior of the kernel while the system is running, offering more fine-grained control over how your system operates.

There are lots of tunables set for the Linux Kernel that dictate how the system will handle a variety of system aspects. As an example, there's a tunable for the maximum number of files that a Linux system can have open at any one time, called 'fs-file-max'

View all tunables:
sysctl -a 
View specific tunable:
sysctl tunable-name
Change tunable value (doesn't persist reboot):
sysctl -w tunable-name=newvalue
Permanently change tunable value

Specifically where this can be done is OS dependent, a typical location is /etc/sysctl.d

Create a new file ie 00-custom-settings.conf

contents:
tunable-name=newvalue