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)

Snapshots

Cisco Unified Computing Systems (UCS) through Cisco Virtual Machine Fabric Extender (VM-FEX) distributed switches support the following features for migration and resource management of virtual machines which use DirectPath I/O:

vMotion

Hot adding and removing of virtual devices

Suspend and resume

High availability

DRS

Snapshots

See Cisco VM-FEX documentation for details on supported switches and switch configuration information.

You can configure passthrough networking devices 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.

You can configure a passthrough 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 Web Client.

Generally, you cannot migrate a virtual machine configured with a passthrough PCI device through vMotion. However, Cisco Unified Computing Systems (UCS) through Cisco Virtual Machine Fabric Extender (VM-FEX) distributed switches support migration of virtual machines.