MPIO is an optional feature in Windows Server 2012 R2, and is not installed by default. To install MPIO on your server running Windows Server 2012 R2, perform the following steps.

  1. Open Server Manager. To open Server Manager, click Start, point to Administrative Tools, and then click Server Manager.

  2. In the Server Manager tree, click Features.

  3. In the Features area, click Add Features.

  4. In the Add Features Wizard, on the Select Features page, select the Multipath I/O check box, and then click Next.

  5. On the Confirm Installation Selections page, click Install.

  6. When the installation has completed, on the Installation Results page, click Close. When prompted to restart the computer, click Yes.

  7. After restarting the computer, the computer finalizes the MPIO installation.

  8. Click Close.

Ref: https://technet.microsoft.com/en-us/library/ee619752(v=ws.10).aspx