Scalability of ocserv

[Valentin Sawadski]

Hello everyone,

I was wondering if there is any reference as to how big OpenConnect's
ocserv can scale in the terms of simultaneous connected clients?

Assuming the clients generate little traffic (less than 1 Megabyte per
Minute), how many connections could a dedicated server handle?

I noticed that ocserv creates a new TUN device for each connected
client. Looking at the following discussion on the maximum number of
networking interfaces in Linux I found this limit (see
https://lists.fedoraproject.org/pipermail/users/2010-September/383512.html)

> > On Fri, 2010-09-24 at 15:02 -0700, byrdca at gmail.com wrote:
> > Today I was asked about the maximum number of NICs supported by the
> > Linux kernel.  My initial response was "probably more than you need".
> > looked in include/linux/limits.h, I didn't expect to find it but that
> > was my first thought.  I then started digging through drivers/net but
> > I soon got lost.  I'm after the hard data for the maximum number of
> > Its been bothering me that I didn't know where to find the answer.  I
> > ethernet cards a modern Linux system supports, anyone have any ideas
> > on where I find this data?
>
> Looking at the code (especially, register_net_dev) it seems that there
> are two possible limits:
> 1. Ethernet device name must not exceed 16 bytes.
> 2. Total number of network devices must not exceed 32768.
> (const int max_netdevices = 8*PAGE_SIZE in __dev_alloc_name)
>
> - Gilboa

Which does not seem very confident as I hardly doubt that the Linux
networking stack is capable of handling so many network interfaces
efficiently.

I would be very glad about any confirmed scalability tests. Thanks!

Best Regards

-- 
Valentin Sawadski
Founder & Embedded Software

Tel.: +49 - (0) 89 - 716 77 86 - 15
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