OpenVPN Support Forum

We have a project, and we want to use open vpn for our project, but there is an issue that we don’t know how many clients can connect to an open vpn server.
I know it may be related to hardware configuration of server PC. If that, could you please tell me how many clients can connect to open vpn server that have a standard hardware configuration.
I think it is better to take a instance for us, like 200 clients can connect to server, the server’s hardware configuration is:

CPU: Intel(R) Core(TM) i3 CPU 540 @ 3.07GHz (4 cores)
2GB RAM
Linux 2.6 (Debian 6)
……

If we add the RAM to 4G, how many clients can be connected to server? and if we change a better CPU? Could you please explain it to us in details?

PS: we don’t use this hardware configuration, I just take it for example.

is anyone know about this?

Openvpn does not seem to need much CPU.

My site has multiple thousands of clients connected on three clusters, and each server (which are kvm or xen-based virtual machines running on top of a Scientific Linux 6.3 host) has only one virtual CPU core allocated and typically run at only 5% to 10% CPU usage. Each server handles about 2000 simultaneous clients with 2GB of RAM and 4GB of swap. They use all the RAM and about 1GB of swap. Openvpn is using 90% of the memory in use.

For a server that is hosting 2000 clients, we see RAM usage of about 3 GB. It doesn't seem to mind much if you use up all the ram and get into swap a bit.

If the above scenario holds true for other users, it seems like you should be able to host approximately 1000 clients per 1.5GB of RAM if you didn't want to use any swap and were looking for best performance.

Wirehead,

This is stunning -I figured that the server would max out at about 50 users connected via LTE and sending data. My testing was done on a dual core 4GB system with 20 devices running and using a network to do file transfers - I saw 40% CPU utilization. What kind of traffic are you sending through your servers? can you tell me more about your config? Seems like I may have missed something pretty basic.