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11.2. Limiting Maximum Number of Processes Available for the Oracle User

After reading the procedure on, Section 11.1, “Limiting Maximum Number of Open File Descriptors for the Oracle User” you should now have an understanding of "soft" and "hard" limits and how to change shell limits.
To see the current limit of the maximum number of processes for the oracle user, run: 
$ su - oracle
$ ulimit -u

Note

The ulimit options are different for other shells.
To change the "soft" and "hard" limits for the maximum number of processes for the oracle user, add the following lines to the /etc/security/limits.conf file: 
oracle           soft    nproc          2047
oracle           hard    nproc          16384
To make this change permanent, you could add "ulimit -u 16384",for bash, to the ~oracle/.bash_profile file which is the user start up file for the bash shell on Red Hat Enterprise Linux (to verify your shell execute echo $SHELL). To do this you could simply copy and paste the following commands for oracle's bash shell: 
su - oracle
cat >> ~oracle/.bash_profile << EOF
ulimit -u 16384
EOF
To make the above changes permanent, you could also set the soft limit equal to the hard limit in /etc/security/limits.conf: 
oracle           soft    nproc          16384
oracle           hard    nproc          16384