Horrible upload performance with virtio and Kernel 4.19.
I'm having some issues with a fresh install of Debian 10.
Out of the box, the network performance is quite horrible. I'm on a KVM host and using virtio as driver.
Windows Server 2019 and Debian 9 can reach speeds up to 1000/100mbit, but Debian 10 seems like the upload is capped to exactly 4.01mbit/s.
On subsequent tests i get 3.76, 3.9, 3.1, 2.9, 3.81 and a lot of times exactly 4.01mbps.
If i look at the network graph i can see that while the download has a steady curve, upload starts with a spike and then goes down completely and dies until the speedtest expires.
What could it be? I tryed asking everywhere but i really can't find anything around about this issue...
Did you update sysctl settings for the network? The default in 10 may be different than the previous versions. This would be the first thing I would check.
maybe something like:
I have the same problem. Php-friends, Debian 10.
Did you try with another os? Does it work that way?
It's fresh install. What you mean?
Didn't try. I don't have the opportunity, server already used for production.
Nope. Still exactly 4.01mbit of upload. (I've added those lines to /etc/sysctl.d/99-sysctl.conf, that's how it works, right?)
Usually /etc/sysctl.conf and then you run 'sysctl -p' to apply them.
Nope. Still stuck at 4.01
Hmm, are you installing from a template or ISO? If ISO I am interested in testing this my self, let me know and I will spin up a quick VM and see if I can replicate the issue.
this is bug of speedtest not debian. I have the same on ubuntu 18.04
I've had the same on ubuntu 18.04.
Happening to me both by installing using Debian 10 netinstall, but also by upgrading a Debian 9 template to kernel 4.19
Same here. Ubuntu 18.04
You may be right. Getting much higher speeds with iperf3.
Yes you are right. In any other case i can use full 1 Gbit/sec.
If that is true then a library the speedtest is using is causing the slow down.
I am in the middle of spinning up a VM on my dev box to see if I can replicate any other network issues, are they only limited to the speedtest-cli, is that the overall consensus here?
Will report my findings as well.
I can't replicate this issue with speedtest-cli my self:
Linux debian10 4.19.0-5-amd64 #1 SMP Debian 4.19.37-5 (2019-06-19) x86_64 GNU/Linux
It seems I don't see that same limitation you guys were seeing.
set the destination server from any other country, not germany. https://c.speedtest.net/speedtest-servers-static.php
It may have to do with MTU settings or something in your case for more distant servers, however, I don't seems to replicate that here still, even specifying a different server.
I believe it that some are running into this, however, I just can't seem to replicate it here.
same here. speedtest-cli mostly upload 4.xx Mbit/s.
Ohhh, I see the difference in my test VS the others in here. I cloned the git repo and ran the version from there, my guess is a bunch of you used 'apt-get install speedtest-cli' and the version installed from the repo does seem to be broken and work as you reported:
However, if you clone the latest python version from github, it doesn't have this issue:
This has to do with the compiled version in the Debian repo having some issues it seems and maybe the libraries it is leveraging. So this isn't something specific to Debian 10 but to that specific package and the libraries it is compiled against, I would bet.
Same here on Debian 10, but only with speedtest-cli
This is the bug of speedtest-cli which is already known on Ubuntu 18.04. try other test such as bench/nench.