If you create a domain with virt-manager, it does not always add the appropriate ‘virtio’ entry to the xml file for your VM.
If this is the case, you will notice that network speeds on the VM will not break 10/100 speeds.
To fix this, edit the xml file
vi /etc/libvirt/qemu/vm.xml
Make sure your network block looks like this (keep your MAC address the same)
<interface type='network'>
<mac address='00:16:36:0b:4c:9c'/>
<source network='default'/>
<model type='virtio'/>
</interface>
Shut down the VM and confirm it’s shut down
virsh shutdown vm
# virsh list
Connecting to uri: qemu:///system
Id Name State
----------------------------------
If you do not see your vm “running” you can proceed. If it’s still running you need to shut it down another way.
Update the xml definition
virsh define /etc/libvirt/qemu/vm.xml
Start the domain
virsh start vm
Log into the VM and test with a 1GB file
dd if=/dev/zero of=/tmp/test bs=1M count=1000
scp /tmp/test [email protected]:/tmp
You should see transfer speeds above 11-12 megabytes/second.