Open file limits can impact some high-resource applications. 


To check the number of files currently open by all processes in the system, run:


# lsof | wc -l


To check the number of files opened by all processes of a particular user, run the following command. Replace "root" with the username of the user in question.

# lsof -u root | wc -l


To check the maximum file limit of the current user, run:

# ulimit -n


Or to print a summary of all limits, run:

# ulimit -a 


Changing file limits


To adjust file limits, edit the limit.conf file:


# vim /etc/security/limits.conf


username            soft            nofile            65536
username            hard           nofile           100000


Save the file and check the new limit using below command.


# ulimit -n


Note: 

soft limit, is the default max value you get when you login

hard limit, is the max value to which you can raise using the ulimit command