Using a nodejs server and client with socket.io I can let 14k clients connect. Slightly less even when using clustering.
Neither CPU or RAM are exhausted. Except for the automatic ping that socket.io does by itself no data is transmitted.
The transport is set to only use 'websocket', no polling!
More clients just fail with the reason "timeout".
What could cause this?
I could understand if the machine is not powerful enough. But then I would expect the server to randomly drop clients anyway and not stay at a specific amount everytime I try it.
Edit: this is on Windows using web storm, I will test on a Linux machine when I can.