6.7

A USB device is available to only one powered-on virtual machine at a time. When a virtual machine
connects to a device, that device is no longer available to other virtual machines or to the client computer.
When you disconnect the device from the virtual machine or shut the virtual machine down, the device
returns to the client computer and becomes available to other virtual machines that the client computer
manages.
For example, when you connect a USB mass storage device to a virtual machine, it is removed from the
client computer and does not appear as a drive with a removable device. When you disconnect the
device from the virtual machine, it reconnects to the client computer's operating system and is listed as a
removable device.
USB 3.0 Device Requirements
Starting with vSphere 5.5 Patch 3, USB 3.0 devices are available for passthrough not only from a client
computer to a virtual machine, but also from an ESXi host to a virtual machine. USB 3.0 devices still have
the following virtual machine configuration requirements:
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The virtual machine that you connect the USB 3.0 device to must be configured with an xHCI
controller and have a Windows 8 or later, Windows Server 2012 and later, or a Linux guest operating
system with a 2.6.35 or later kernel.
Avoiding Data Loss
Before you connect a device to a virtual machine, make sure the device is not in use on the client
computer.
If the vSphere Client disconnects from the vCenter Server or host, or if you restart or shut down the client
computer, the device connection breaks. It is best to have a dedicated client computer for USB device
use or to reserve USB devices connected to a client computer for short-term use, such as updating
software or adding patches to virtual machines. To maintain USB device connections to a virtual machine
for an extended time, use USB passthrough from an ESXi host to the virtual machine.
Connecting USB Devices to a Client Computer
You can connect and chain any multiple low, full, and high- or super-speed USB hubs and devices to a
client computer. Careful planning and knowledge of hub behavior and limitations can help ensure that
your devices work optimally.
USB physical bus topology defines how USB devices connect to the client computer. Support for USB
device passthrough to a virtual machine is available if the physical bus topology of the device on the client
computer does not exceed tier seven. The first tier is the USB host controller and root hub. The last tier is
the target USB device. You can cascade up to five tiers of external or internal hubs between the root hub
and the target USB device. An internal USB hub attached to the root hub or built into a compound device
counts as one tier.
vSphere Virtual Machine Administration
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