Step 1.) Edit the limits.conf in the /etc/security directory using any Linux text editor.
Step 2.) Add the following substituting XXXX with a number that will become the new hard and soft limits for open files:
root hard nofile XXXX root soft nofile XXXX
*NOTE* If you are using an account other than the root account to run Syslog-ng, please change "root" above to the user-name used for running Syslog-ng.
Step 3.) Save the file and restart the Linux host to apply the changes permanently.