[PVE-User] The low network throughput obsered on Open vSwitch bridge.

[Hongyi Zhao <hongyi.zhao@gmail.com>]

I install the pve on an I7 8886U machine with 6 full-duplex gigabit
network cards. The network configuration of the pve host is shown
below:

<quote>
root@pve:~# cat /etc/network/interfaces
# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

auto lo
iface lo inet loopback

auto enp1s0
iface enp1s0 inet manual
        ovs_type OVSPort
        ovs_bridge vmbr0

auto enp2s0
iface enp2s0 inet manual
        ovs_type OVSPort
        ovs_bridge vmbr1

iface enp3s0 inet manual
iface enp4s0 inet manual
iface enp5s0 inet manual
iface enp6s0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 192.168.10.254/24
        gateway 192.168.10.1
        ovs_type OVSBridge
        ovs_ports enp1s0

auto vmbr1
iface vmbr1 inet manual
        ovs_type OVSBridge
        ovs_ports enp2s0
</quote>

Now I use scp to transfer file from pve (192.168.10.254) to another
physical machine (192.168.10.100) or vice versa, but run the following
two commands in order:

root@pve:~# scp macOS-10.13.qcow2 werner@192.168.10.100:/dev/null
werner@192.168.10.100's password:
macOS-10.13.qcow2                              37% 6209MB  83.6MB/s   02:01 ETA

werner@X10DAi:~$ scp macOS-10.13.qcow2 root@192.168.10.254:/dev/null
root@192.168.10.254's password:
macOS-10.13.qcow2                                        30% 1408MB
53.5MB/s   01:00 ETA

As you can see, the show different network transfer speed. OTOH, if I
run the above two commands simultaneously, the results will look like
the following:

werner@X10DAi:~$ scp macOS-10.13.qcow2 root@192.168.10.254:/dev/null
root@192.168.10.254's password:
macOS-10.13.qcow2                                        17%  811MB
26.0MB/s   02:26 ETA

root@pve:~# scp macOS-10.13.qcow2 werner@192.168.10.100:/dev/null
werner@192.168.10.100's password:
macOS-10.13.qcow2                              13% 2205MB  51.7MB/s   04:34 ETA


Any hints for the above observations and results will be highly appreciated.

Regards
-- 
Assoc. Prof. Hongyi Zhao <hongyi.zhao@gmail.com>
Theory and Simulation of Materials
Hebei Polytechnic University of Science and Technology engineering
NO. 552 North Gangtie Road, Xingtai, China