Why do I get "Too many open files" on my Linux Load Generator?

During the load test, the Load Generator may use many resources on your machine.

One of these resources is the number of sockets that needs to be opened at the same time on the computer. On Linux, sockets, files, directories...are file descriptors. By default, the number of file descriptors that can be opened at the same time is 1024.

Since the Load Generator will open many sockets, the default value is too low. In that case, the system will raise that error of "Too many open files".

The command ulimit -n provides you the current configured value.

To avoid the "Too many open files" message, you have to increase the default value. You are advised to increase it up to 65534 using that command ulimit -n 65534 (or consult your Systems Administrator).

To persist that modification, you have to modify that file: /etc/security/limits.conf

Here is an example of configuration:

neoload soft nofile 4092
neoload hard nofile 65534

Here neoload is the user used to start your NeoLoad Agent. A reboot is needed to apply the modification.

The new ulimit value is available on the Load Generator logs available on the NeoLoad interface.

For more information about that error, see Troubleshooting.

With that new configuration, your Load Generator will fully use your machine resources.