Howdy Everyone, I’m hoping someone might be able to point me in the correct direction. I’m running Unraid, and using VFIO to pass through my AMD 5600XT graphics card to and Ubuntu Guest. This works swell, except when it comes to networking. I also have a windows guest, and when I run on windows I’m able to saturate the network connection (as reported by speediest(DOT)net and fast(DOT)com) usually around 1.5 - 1.7 gbps. However when I run the ubuntu host the best I’m able to get is around 580 mbps. I can’t figure out exactly what is wrong and I’m hoping someone here might know. Both VMs have their Network Bridge set to br0 and the Network Model set to virtio-net. Below you will find the output of ip a from within the ubuntu guest
$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0. 1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 52:54:88:88:88:88 brd ff:ff:ff:ff:ff:ff
inet 10.2.1. 4/16 brd 10.2.255.255 scope global dynamic noprefixroute enp3s0
valid_lft 2047sec preferred_lft 2047sec
inet6 fe80::7556:8050:a688:6d42/64 scope link noprefixroute
valid_lft forever preferred_lft forever
The virtio network mount is terribly slow. Its not just an unraid thing, its a virtio thing. Consider using either an nfs or smb mount to regain full performance.
Ok… sorry. I should hold off reading questions until after my first cup of coffee.
So… your using an offsite speed test to test the network performance of your two unraid guest VMs. Do you have another machine on the local network where you could do performance testing to exclude the public speed test site? Its possible that the 3rd party site is treating the 2 guests differently somehow.
I would suggest using iperf3 to test on your local network.
It looks as if the ubuntu guest is being held to around 1Gb connection speed.
Unfortunately my unraid server is currently still using a single 1Gb connection to my home LAN. As such I do not see a speed degradation in my guest VMs. They are able to saturate the host connection speed of 1Gb/s (~840Mbps after TCP overhead).
Hopefully one of the other more advanced users around here can chime in on why an ubuntu guest might behave different than a Windows guest in this configuration. If I had to guess, I would be willing to bet that not all the right options are set in the ubuntu kernel build to best support virtual interface connections. As I said, though, this is just a guess on my part.
Thanks for your help! I seem to have stumbled upon a solution. changing the Network model from virtio-net to virtio seems to fix the issue and I’m able to nearly saturate the connection inside of ubuntu.
So, using my unraid server as the iperf3 server and then running the speed test from the VM, my unraid machine is able to internally run the test at ~22 Gb/s.
Internally, it does not appear that unraid is bottlenecked. My setup is an X470 motherboard with a 2700X cpu. All in a stock/non overclocked configuration.