You can add multiple USB devices to a virtual machine when the physical devices are connected to the client computer on which you run the vSphere Client. The vSphere Client must be logged in to a vCenter Server instance that manages the ESXi host where the virtual machine resides. USB passthrough technology supports adding multiple USB devices, such as security dongles, mass storage devices, and smartcard readers to virtual machines.
How USB Device Passthrough Technology Works
The USB controller is the USB hardware chip that provides a USB function to the USB ports that it manages. The USB controller hardware and modules that support USB 3.1 SuperSpeedPlus, USB 3.1 SuperSpeed, 2.0, and USB 1.1 devices must be available on the virtual machine. Two USB controllers are available for each virtual machine. The controllers support multiple USB devices, such as USB 3.1 SuperSpeedPlus, USB 3.1 SuperSpeed, 2.0, and 1.1. The controller must be present before you can add USB devices to the virtual machine.
You can add up to 20 USB devices to a virtual machine, which is the maximum number of devices supported for a simultaneous connection to one virtual machine. You can add the devices only one at a time.
The virtual machine retains its connection to the device while it is in an S1 standby state. USB device connections are preserved when you migrate virtual machines to another host in the data center.
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 down the virtual machine, 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 3.1 SuperSpeed Device Requirements
- The virtual machine must have an enabled xHCI controller, 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 that the device is not in use on the client computer.
If the vSphere Client disconnects from the vCenter Server system 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.
USB 3.1 SuperSpeedPlus Device Requirements
Starting with vSphere 7.0, USB 3.1 SuperSpeedPlus devices are available for passthrough at their maximum speed (SuperSpeedPlus), not only from a client computer to a virtual machine, but also from an ESXi host to a virtual machine. To operate their maximum transfer speed, USB 3.1 SuperSpeedPlus devices have the following virtual machine configuration requirements:
- The virtual machine must have an enabled xHCI controller, Windows 10 or later, Windows Server 2016 and later, or a Linux guest operating system with a 4.6 or later kernel.
- Verify that the virtual machine hardware is of version 17 or later.
- For requirements and steps how to enable the USB 3.1 SuperSpeedPlus, see the VMware knowledge base article https://kb.vmware.com/s/article/70748.