You can add multiple USB devices to a virtual machine when the physical devices are connected to an ESXi host. USB passthrough technology supports adding USB devices, such as security dongles and mass storage devices, to virtual machines that reside on the host to which the devices are connected.
How USB Device Passthrough Technology Works
When you attach a USB device to a physical host, the device is available only to virtual machines that reside on that host. The device cannot connect to virtual machines that reside on another host in the data center.
A USB device is available to only one virtual machine at a time. When you connect a device to a powered on virtual machine, the device is not available to connect to other virtual machines that run on the host. When you remove the active connection of a USB device from a virtual machine, it becomes available to the other virtual machines that run on the host.
To connect a USB passthrough device to a virtual machine that runs on the ESXi host where the device is physically attached, you require an arbitrator, a controller, and a physical USB device or device hub.
- USB Arbitrator
- Manages connection requests and routes the USB device traffic. The arbitrator is installed and enabled by default on ESXi hosts. It scans the host for USB devices and manages the device connection among virtual machines that reside on the host. It routes the device traffic to the correct virtual machine for delivery to the guest operating system. The arbitrator monitors the USB device and prevents other virtual machines from using it until you release it from the virtual machine it is connected to.
- USB Controller
The USB hardware chip that provides a USB function to the USB ports that it manages. The virtual USB controller is the software virtualization of the USB host controller function in the virtual machine.
USB controller hardware and modules that support USB devices, such as USB 3.1 SuperSpeedPlus, USB 3.1 SuperSpeed, USB 2.0, and USB 1.1 must exist on the host. A controller must be present before you can add a USB device to the virtual machine.
The USB arbitrator can monitor a maximum of 15 USB controllers. Devices connected to controllers numbered 16 or greater are not available to the virtual machine.
- USB Devices
- 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. The maximum number of USB devices supported on a single ESXi host for a simultaneous connection to one or more virtual machines is also 20. For more information, see Supported USB device models for passthrough from an ESX or ESXi host to a virtual machine.
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.
USB 3.1 SuperSpeedPlus Device 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 USB 3.1 SuperSpeedPlus, see the VMware knowledge base article https://kb.vmware.com/s/article/70748.