The Linux kernel has about 1,000 tunable parameters. These default to reasonable values for common usage, which means they are not perfect for anyone.
Tuning the Linux kernel with sysctl
Getting started
The sysctl command is available on all Linux systems. You must be root to modify kernel parameters.
The sysctl command will change the parameter value immediately, but the value will revert to the original value upon reboot unless you add a line to define the parameter to /etc/sysctl.conf.
It's a good policy to change a value manually and test it before modifying sysctl.conf. You can make a system unbootable by applying bad values to /etc/sysctl.conf.
