Comments on: Linux increase the maximum number of open files or file descriptors

By: Adam HP

Adam HP — Thu, 25 Feb 2010 09:18:07 +0000

To clear up any confusion for increasing the limit on Red Hat 5.X systems:

# echo “fs.file-max=70000″ >> /etc/sysctl.conf
# sysctl -p
# echo “* hard nofile 65536″ >> /etc/security/limits.conf
# echo “session required pam_limits.so” >> /etc/pam.d/login
# ulimit -n -H
65536

In summary set your max file descriptors to a number higher than your hard security ‘nofile’ limit to leave room for the OS to run.

By: hywl51

hywl51 — Wed, 28 Oct 2009 05:44:52 +0000

“Use the following command command to display maximum number of open file descriptors:
cat /proc/sys/fs/file-max
Output:

75000

75000 files normal user can have open in single login session. ”

I think 75000 should mean the whole system can support 75000 open files at most , not for per user login.

By: shankar

shankar — Fri, 19 Jun 2009 15:58:36 +0000

you could use the following command to check if the given change reflected

#ulimit -n -H

that gives the hard value…

By: Arstan

Arstan — Wed, 23 Apr 2008 02:23:00 +0000

I’m trying to make 8192 on Ubuntu 7.10, adding

* soft nofile 8192
* hard nofile 8192

doesn’t work, but when i do change * to username(lets say root) it applies.

So how to change it system wide?

By: jackson

jackson — Sat, 01 Dec 2007 01:54:42 +0000

Red Hat configuration requires the following line to be added for /etc/security/limits to work.

in /etc/pam.d/login
session required pam_limits.so

By: vivek

vivek — Fri, 14 Sep 2007 04:32:32 +0000

baka.tom / jason,

The FAQ has been updated for latest kernel. It should work now. Let me know if you have any more problems.

bourne, thanks for pointing out user level or group level filelimit option.

I appreciate all feedback.

By: jason

jason — Thu, 13 Sep 2007 20:55:03 +0000

I am running “Red Hat Enterprise Linux ES release 4 (Nahant Update 5)” and followed the instructions above. Like “baka.tom”, I was unable to see the change reflected by typing “ulimit -n”. I don’t know if this is a problem, but it certainly reduces the credibility of this article (unless I screwed up, of course).

By: bourne

bourne — Thu, 13 Sep 2007 14:10:48 +0000

/etc/sysctl.conf is good for the system-wide amount, but don’t forget that users also need different limits. See /etc/security/limits.conf (Debian, Redhat, SuSE all have it, probably most others as well) to assign specific limits on per-group, per-user, and default basises.

By: baka.tom

baka.tom — Tue, 11 Sep 2007 23:34:45 +0000

i tried this on a CentOS (which by the way, i’ve decided the worst linux distribution ever), and it doesn’t seem to work. ulimit -n still says 1024, even after logout, even after reboot.

By: Sathish A

Sathish A — Tue, 28 Aug 2007 23:40:27 +0000

how to increase in a Redhat linux server? How to find the location of sysctl.conf file or how to find in which file the limit has been set?

thanks in advance