Slow network performance inside VM

Community Support
1

Hello,

I have a server running OpenNebula based on Debian Stretch. I then virtualize using KVM.
I noticed that the network performance in the VM is much slower than directly on the host system.

I ran a script which downloads test files from various mirrors via wget.
Strange is that almost all mirrors in the VM are a lot slower, but others achieve a similar performance as on the host system (Cachefly mirror or IP-Projects speedtest).

I could not yet reproduce what the speed depends on. The system was empty each time the test was run, so no other processes were running in the background.

Anybody have any idea what might be causing this?
I am using a routed network setup on the system.

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2

Did you use virtio as network device model? What is the output of ‘lspci |grep -i ethernet’ command inside VM?

3

Try to use virtio model at your VMs.

NIC = [
...
  MODEL = "virtio",
...]

NIC_DEFAULT = [
  MODEL = "virtio" ]
4

Thank you, I solved it by using virtio.