6.5.1

Table Of Contents
Prerequisites
Enable high-performance network I/O on at least one Cisco UCS port profile on a supported Cisco VM-
FEX distributed switch. For supported switches and switch configuration, see documentation at the CIsco
websitehttp://www.cisco.com/go/unifiedcomputing/b-series-doc .
Procedure
1 Locate the virtual machine in the vSphere Web Client.
a Select a data center, folder, cluster, resource pool, or host and click the VMs tab.
b Click Virtual Machines and double-click the virtual machine from the list.
2 Power off the virtual machine.
3 On the Configure tab of the virtual machine, expand Settings and select VM Hardware.
4 Click Edit and select the Virtual Hardware tab in the dialog box displaying the settings.
5 Expand the Memory section, and set the Limit to Unlimited.
6 Expand the Network adapter section to configure a passthrough device.
7 Next to DirectPath I/O, click Enable.
8 From the network drop-down menu, select a port profile with high performance enabled and click OK.
9 Power on the virtual machine.
Single Root I/O Virtualization (SR-IOV)
vSphere 5.1 and later releases support Single Root I/O Virtualization (SR-IOV). You can use SR-IOV for
networking of virtual machines that are latency sensitive or require more CPU resources.
Overview of SR-IOV
SR-IOV is a specification that allows a single Peripheral Component Interconnect Express (PCIe) physical
device under a single root port to appear as multiple separate physical devices to the hypervisor or the
guest operating system.
SR-IOV uses physical functions (PFs) and virtual functions (VFs) to manage global functions for the SR-
IOV devices. PFs are full PCIe functions that are capable of configuring and managing the SR-IOV
functionality. It is possible to configure or control PCIe devices using PFs, and the PF has full ability to
move data in and out of the device. VFs are lightweight PCIe functions that support data flowing but have
a restricted set of configuration resources.
The number of virtual functions provided to the hypervisor or the guest operating system depends on the
device. SR-IOV enabled PCIe devices require appropriate BIOS and hardware support, as well as SR-
IOV support in the guest operating system driver or hypervisor instance. See SR-IOV Support.
vSphere Networking
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