How to handle network problems
Networking inside some VM's was so slow as to be non-functional; I
finally found https://bugzilla.redhat.com/show_bug.cgi?id=855640,
which suggested (note 11)
ethtool -K eth0 gro off
With that change, everything worked well, except that speedtest.net
was not able to connect for the upload speed test. So I'm not sure if
the problem is completely fixed.
If anyone has suggestions about diagnosing or solving the problem,
that would be great.
I am also wondering if I should let someone know about this problem
since the solution is really just a work-around. I'm not sure if the
real problem is with the virtio drivers, the hardware network drivers,
the bridging code, kvm,....
I had the problem with a Windows 7 VM (with RedHat's virtio drivers),
but there are reports of similar trouble with Linux guests. There is
also a very similar report with newer kernels
(http://askubuntu.com/questions/503863/poor-upload-speed-in-kvm-guest-with-virtio-eth-driver-in-openstack-on-3-14
and references from there), but since that is reported as a regression
it may be different.
The vm is running under KVM under libvirt, via virt-manager. Using
bridged networking from libvirt and virtio from inside the VM.
Thanks.
Ross Boylan
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