* soft nproc 400
* hard nproc 500
(If you hit 400 processes, the system will warn you. If you hit 500, the system will block you)
Alternatively if you do not wish to set a limit to the number of processes that can be run on your servers due to the particular application, you can also
* soft nproc unlimited
* hard nproc unlimited
You do not need to reboot to effect the settings, just relogin and the users will be subjected to the /etc/security/limits.conf configuration file