5.2. Editing IO Threads

If a virtual machine has more than one disk, you can enable or change the number of IO threads to improve performance.

Procedure 5.2. Editing IO Threads

  1. Select the virtual machine to be edited.
  2. Click Edit.
  3. Click the Resource Allocation tab.
  4. Select the IO Threads Enabled check box. Red Hat recommends using the default number of IO threads, which is 1.
  5. Click OK.
  6. Click the Reboot icon to restart the virtual machine.
    If you increased the number of IO threads, you must reactivate the disks so that the disks will be remapped according to the correct number of controllers:
    1. Click the Shutdown icon to stop the virtual machine.
    2. Click the Disks tab in the details pane.
    3. Select each disk and click Deactivate.
    4. Select each disk and click Activate.
    5. Click the Run icon to start the virtual machine.
You can view the IO threads by clicking Vm Devices in the details pane.
The assignment of disks to controllers displays only in the XML, not in the Administration Portal.

Procedure 5.3. Viewing Disk Controller Assignment

  1. Log in to the host machine.
  2. Use the dumpxml command to view the mapping of disks to controllers: 
    # virsh -r dumpxml virtual_machine_name