29.2.2.3 Optional Configuration Changes

This section describes optional changes that can be made to the configuration after installation is complete.

Note

The optional configuration changes are only relevant if you completed a Default type of installation, are running Oracle Linux, and have control of the host system. If you have completed a Custom installation and migrated your VM from the OCI-C to Oracle Cloud Infrastructure environment, you do not have access to the host.

The changes that are described here require that the host system is running the latest supported virtualization packages, which are available in the ol7_kvm_utils Yum repository on the Oracle Linux yum server or in the ol7_x86_64_kvm_utils or ol7_aarch64_kvm_utils channels on ULN.

If you have not already done so, enable the appropriate channel or repository and install the packages from this location before proceeding. See Section 29.1.2, “Yum Repositories and ULN Channels for Virtualization Packages” for more information. If you perform an upgrade of the virtualization packages, you might need to restart any running virtual machines for the changes to take effect.

Configuring Block Drivers

The Oracle VirtIO Drivers for Microsoft Windows provide block drivers that improve disk performance on Microsoft Windows guests. However, guests do not automatically start by using the Oracle VirtIO Drivers for Microsoft Windows storage drivers after installation. As a result, guests cannot use the paravirtualized storage drivers for boot disks. You must configure each guest to use paravirtualized storage drivers instead of emulated disks after installation.

To configure block drivers after installation:

  1. Ensure you have installed the Oracle VirtIO Drivers for Microsoft Windows.

  2. Stop the guest if it is running.

  3. Create a new temporary image that you can add to the guest as a second disk. For example, run:

    # qemu-img create -f qcow2 disk_name.qcow2 1G
  4. Add the disk you created to the guest.

  5. Specify virtio as the bus type for the disk you added and then start the guest. Microsoft Windows will locate the disk drivers and complete the installation at this point.

  6. Change the bus type for the boot disk to virtio and then start the guest.

    Microsoft Windows then installs the Oracle VirtIO Drivers for Microsoft Windows block driver on the boot disk.

  7. Detach the temporary disk from the guest.

Setting the MTU Size for Virtual Machines

The Oracle VirtIO Drivers for Microsoft Windows override the maximum transmission unit (MTU) settings in the virtual network adapters for Microsoft Windows guests. After you have successfully installed and verified the Oracle VirtIO Drivers for Microsoft Windows, set the MTU for each guest as follows:

  1. Open the Microsoft Windows virtual machine.

  2. Open the control panel, then locate and open the Device Manager window.

  3. Expand Network adapters and select the appropriate Oracle VirtIO Ethernet Adapter.

  4. Right-click the adapter, select Properties, and then select the Advanced tab.

  5. Select the MTU property and set the value as appropriate.

  6. Click OK to save your changes.