I want to increase the maximum number of open files in Fedora 27, since the default settings are too low:

$ ulimit -Sn
$ ulimit -Hn

First, I ensure that the system-wide setting is high enough, by adding the following line to /etc/sysctl.conf:


Then, I set the user-specific settings by adding the following lines to /etc/security/limits.conf (root must be added separately since the Wildcard matches all users except root):

*     soft  nofile 100000
*     hard  nofile 100000
root  soft  nofile 100000
root  hard  nofile 100000

To ensure that the above settings are actually loaded, I have added the following line to /etc/pam.d/login:

session required pam_limits.so

After rebooting my computer and logging in, I still get the same results for ulimit -Sn and ulimit -Hn. Only the system-wide setting have been set:

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

I'm a bit at a loss as to what to do... Anybody have any ideas how I might diagnose/solve this?

  • You could add debug to the line in /etc/pam.d/login. I just double checked on a FC27 and the pam_limits.so is also in the pam modules system-auth, sudo, runuser, password-auth... also check with journalctl -f which pam module is triggered on login. – Thomas Mar 4 '18 at 18:02

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