Increase Maximum open file in Linux

It is important for a production server to set the maximum open file limit as you might get over limit on your web services, database services, email services, and etc.

First of all, you may list the maximum of open file limit as command below.
cat /proc/sys/fs/file-max

Then you may increase the file description limit as command below.
sysctl -w fs.file-max=150000

The above command force the kernel to limit the maximum open file limit but you will need to perform the change from /etc/sysctl.conf in case the setting change after a reboot.
vi /etc/sysctl.conf

Append the setting as below.
fs.file-max = 150000

Then save it and run the command as below.
sysctl -p