DirectPath I/O allows virtual machine access to physical PCI functions on platforms with an I/O Memory Management Unit.
The following features are unavailable for virtual machines configured with DirectPath:
- Hot adding and removing of virtual devices
- Suspend and resume
- Record and replay
- Fault tolerance
- High availability
- DRS (limited availability. The virtual machine can be part of a cluster, but cannot migrate across hosts)
Enable Passthrough for a Network Device on a Host
Passthrough devices provide the means to use resources efficiently and improve performance of your environment. You can enable DirectPath I/O passthrough for a network device on a host.
- Browse to a host in the vSphere Client navigator.
- On the Configure tab, expand Hardware and click PCI Devices.
- To enable DirectPath I/O passthrough for a PCI network device on the host, click Edit.
A list of available passthrough devices appears.
Icon Description green icon A device is active and can be enabled. orange icon The state of the device has changed, and you must reboot the host before you can use the device.
- Select the network device to be used for passthrough and click OK.
The selected PCI device appears in the table. Device information is displayed at the bottom of the screen.
Configure a PCI Device on a Virtual Machine
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 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 Client.
- Select a data center, folder, cluster, resource pool, or host and click the VMs tab.
- Click Virtual Machines and click the virtual machine from the list.
- Power off the virtual machine.
- From the Actions menu, select Edit Settings.
- Select the Virtual Hardware tab in the dialog box displaying the settings.
- Expand the Memory section, and set the Limit to Unlimited.
- Click the Add new device button and under Other devices, select PCI Device.
The New PCI device drop-down menu is added to the list in the Virtual Hardware tab.
- From the New PCI device drop-down menu select the passthrough device to use, and click OK.
- Power on the virtual machine.