Passthrough devices provide the means to more efficiently use resources and improve performance in your environment. You can configure a passthrough PCI device on a virtual machine in the vSphere Web Client.
When using passthrough devices with a Linux kernel version 2.6.20 or earlier, avoid MSI and MSI-X modes because these modes have significant performance impact.
Verify that a passthrough networking device is configured on the host of the virtual machine. See Enable Passthrough for a Network Device on a Host.
- Locate the virtual machine in the vSphere Web Client.
- Select a data center, folder, cluster, resource pool, or host and click the VMs tab.
- Click Virtual Machines and double-click the virtual machine from the list.
- Power off the virtual machine.
- On the Configure tab of the virtual machine, expand Settings and select VM Hardware.
- Click Edit and select the Virtual Hardware tab in the dialog box displaying the settings.
- Expand the Memory section, and set the Limit to Unlimited.
- From the New device drop-down menu select PCI Device and click Add.
- From the New PCI device drop-down menu select the passthrough device to use, and click OK.
- Power on the virtual machine.
Adding a DirectPath I/O device to a virtual machine sets memory reservation to the memory size of the virtual machine.