How can I increase my open file limit in Ubuntu?
I'm trying to run a script but it keeps hitting the open file limit. When I run
ulimit -n it says 1024. How can I change this, and make it so the change lasts through my next reboot?
This is is a great question.
In order to change these settings permanently you have two options. The first is to make the change in your
sysctl.conf file. You can do this by running:
sudo nano /etc/sysctl.conf
from the command line. This will open up the sysctl.conf file in the nano text editor. While there are some really useful networking settings in there we only need to add one line.
fs.file-max = $VARIABLE
where $VARIABLE is the limit of max files that you need to have open. I would recommend starting with a lowest possible value and working your way up to prevent any unexpected behavior.
You might receive an error to the effect of "sysctl: permission denied on key ‘fs.file-max.'" This isn't the end of the world, it just means we are going to have to move on to the second option.
In this case we are going to run:
sudo nano /etc/security/limits.conf
and add the following lines to the file:
* soft nproc $VARIABLE * hard nproc $VARIABLE * soft nofile $VARIABLE * hard nofile $VARIABLE $USER soft nproc $VARIABLE $USER hard nproc $VARIABLE $USER soft nofile $VARIABLE $USER hard nofile $VARIABLE
You can add this to the bottom of the file, where $VARIABLE is going to be your minimum limit and $USER is the user that is running the script. Next we are going to run:
sudo nano /etc/pam.d/common-session
We are looking for the line
session required pam_permit.so
Which we are going to edit to:
session required pam_limits.so
Then you can go ahead and run to try
ulimit -n which should return $VARIABLE.
I hope this helps you get set up. If you have another way of accomplishing this don't hesitate to let us know!
Thanks. How would I make this apply to the
www-data user running nginx?
As per the
/etc/security/limits.conf example that @tbaka provided, you would replace $USER with
www-data and $VARIABLE with your open files limit.
* soft nproc 1024 * hard nproc 2048 * soft nofile 1024 * hard nofile 2048 www-data soft nproc 1024 www-data hard nproc 2048 www-data soft nofile 1024 www-data hard nofile 2048
Then you can give the
www-data user a quick shell to verify with the
su - www-data -c 'ulimit -Sn' -s '/bin/bash' # soft limit 1024 su - www-data -c 'ulimit -Hn' -s '/bin/bash' # hard limit 2048