[CentOS] OpenVPN throughput

Fri Aug 20 15:54:09 UTC 2010
Gordon Messmer <yinyang at eburg.com>

On 08/19/2010 07:29 AM, Boris Epstein wrote:
> 1) Have you used OpenVPN in a similar setup?

For the hell of it, I ran openvpn on two hosts in a 1Gbps LAN.

> 2) If so what sort of performance did you see?

I was able to copy a 707788800 byte ISO in 55 seconds using the default 
BF-CBC cipher.  I used "nc" to transmit the file.  The same file over 
the non-vpn route took only 17 seconds.  CPU utilization of the 'nc' 
process was rather high in the second test, which probably indicates 
that nc was sending data in fairly small buffers.

I'm at a loss to explain it, but scp was actually much faster, despite 
encrypting the data twice over (though that was happening on different 
CPUs, so probably didn't slow things down much).  scp copied the same 
file in 27 seconds over the VPN, and 20 seconds over the LAN.

> 3) What kind of equipment did you use?

Two Dell Inspiron 531s systems.  One running CentOS 5, the other Fedora 
13.  Both have AMD Athlon64 X2 4000+ CPUs.  Both have D-Link DGE-530T 
Gig-E network adapters.  The MTU between the systems is 9000.