[Openvpn-devel] Tunnel Speed Tunning with many clients connected

[James M. <mac...@ed...>]

Hi Folks,

I have parsed around a bit but have not come up with a solid suggestion 
to increase performance in the following environment :

. +150 clients always on, always via COAX modem 15Mb/s down 1.5Mb/s up.
. OpenVPN-2.0.9 and 2.1rc13 tested, setup as single server
. Server Kernel 2.6.25.4
. Server 64bit
. Server CPU % rarely goes above 30
. Server is fed over a 10G link

Currently we get what appears to be only between 5 and 6 MB/s average 
using this setup.

If only activity is over a single tunnel we can get the expected max 
(about 14Mb/s to the remote site) for the COAX sites. Once traffic 
builds during the day, that number drops.

We know if we hit it locally we can get 160Mb/s. We know if we do hit it 
locally and are getting the 160Mb/s that the COAX tunnels do suffer. 
Starting by almost 1/2 of their normal throughput tunnel speed of almost 
14Mb/s.

So in my small mind, I am thinking we are seeing around 48Mb/s (6MB/s*8) 
used, but that we should be able to get over 150Mb/s. CPU isn't hurting. 
Almost feels like there is a governor slowing down the traffic :).

Important settings from latest config :

verb 1
dev tap
tun-mtu 1500
tun-mtu-extra 32
mssfix 1468
proto udp
ca SSCert.pem
cert servercert.pem
key serverkey.pem
dh dh1024.pem
tls-auth ./tlspass
keepalive 30 63
ping-timer-rem
persist-tun 1
persist-key 1
cipher none
tcp-queue-limit 4096
sndbuf 131072
rcvbuf 131072


Anyone have any words of wisdom :) ?

Thanks,
JES