disk-blockio.xml

<domain type='qemu'>
  <name>QEMUGuest1</name>
  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
  <memory unit='KiB'>219136</memory>
  <currentMemory unit='KiB'>219136</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <os>
    <type arch='i686' machine='pc'>hvm</type>
    <boot dev='hd'/>
  </os>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/bin/qemu-system-i686</emulator>
    <disk type='block' device='cdrom'>
      <source dev='/dev/HostVG/QEMUGuest1'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='1'/>
    </disk>
    <disk type='file' device='disk'>
      <source file='/tmp/idedisk.img'/>
      <target dev='hdc' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='2'/>
      <blockio logical_block_size='512' physical_block_size='512'/>
    </disk>
    <controller type='usb' index='0'/>
    <controller type='ide' index='0'/>
    <memballoon model='virtio'/>
  </devices>
</domain>