Ubuntu open file limit for all users

gistfile1.txt

When you see PHP Warning: something like 
"failed to open stream: Too many open files in /var/www/...
You need to check open file limit as below:

$ ulimit -n
4096

Change the following lines in the file: /etc/security/limits.conf
* soft nofile 4096
* hard nofile 4096

Add the following line in the file: /etc/pam.d/common-session
session required pam_limits.so

http://askubuntu.com/questions/162229/how-do-i-increase-the-open-files-limit-for-a-non-root-user