Error “Too many files open” on CentOS 7

If you are encountering Error messages during login with “Too many open files” and the session gets terminated automatically, it is because the open file limit for a user or system exceeds the default setting and  you may wish to change it

@ System Levels

To see the settings for maximum open files,

# cat /proc/sys/fs/file-max

This value means that the maximum number of files all processes running on the system can open. By default this number will automatically vary according to the amount of RAM in the system. As a rough guideline it will be about 100,000 files per GB of RAM.


To override the system wide maximum open files, as edit the /etc/sysctl.conf

# vim /etc/sysctl.conf
 fs.file-max = 80000000

Activate this change to the live system

# sysctl -p

@ User Level

To see the setting for maximum open files for a user

# su - user1
$ ulimit -n

To change the setting, edit the /etc/security/limits.conf

$ vim /etc/security/limits.conf
user - nofile 2048

To change for all users

* - nofile 2048

This set the maximum open files for ALL users to 2048 files. These settings will require a reboot to activate.


  1. How to correct the error “Too many files open” on Red Hat Enterprise Linux