[CentOS] OpenVPN throughput

[Boris Epstein]

On Fri, Aug 20, 2010 at 11:54 AM, Gordon Messmer <yinyang at eburg.com> wrote:
> 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.
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Gordon, thanks, very helpful.

I thought ethernet NIC's limit MTU to 1500. Just tried to set mine to
9000 and failed - it is OK with values <= 1500 though.

Boris.