21.11. KVM Networking Performance

Procedure 21.4. Switching to the virtio driver

1. Shutdown the guest operating system.
2. Edit the guest's configuration file with the virsh command (where GUEST is the guest's name):

   # virsh edit GUEST

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   The virsh edit command uses the $EDITOR shell variable to determine which editor to use.
3. Find the network interface section of the configuration. This section resembles the snippet below:

   <interface type='network'>
     [output truncated]
     <model type='rtl8139' />
   </interface>
   

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4. Change the type attribute of the model element from 'rtl8139' to 'virtio'. This will change the driver from the rtl8139 driver to the e1000 driver.

   <interface type='network'>
     [output truncated]
     <model type='virtio' />
   </interface>
   

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5. Save the changes and exit the text editor
6. Restart the guest operating system.

1. Create an XML template from an existing guest (in this example, named Guest1):

   # virsh dumpxml Guest1 > /tmp/guest-template.xml
   

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2. Copy and edit the XML file and update the unique fields: virtual machine name, UUID, disk image, MAC address, and any other unique parameters. Note that you can delete the UUID and MAC address lines and virsh will generate a UUID and MAC address.

   # cp /tmp/guest-template.xml /tmp/new-guest.xml
   # vi /tmp/new-guest.xml
   

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   Add the model line in the network interface section:

    <interface type='network'>
     [output truncated]
     <model type='virtio' />
   </interface>
   

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3. Create the new virtual machine:

   # virsh define /tmp/new-guest.xml
   # virsh start new-guest
   

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