You can connect multiple USB devices to ESXi hosts so that virtual machines that run on the hosts can access the devices. The number of devices that you can connect depends on several factors, such as how the devices and hubs chain together and the device type.
Each ESXi host has several USB ports. The number of ports on each host depends on the physical setup of the host. When you calculate the depth of hub chaining, remember that on a typical server the front ports connect to an internal hub.
The USB arbitrator can monitor a maximum of 15 USB controllers. If your system includes controllers that exceed the 15 controller limit and you connect USB devices to them, the devices are not available to the virtual machine.
The host treats USB CD/DVD-ROM devices as SCSI devices. Hot adding and removing these devices is not supported.
If a host has attached USB devices and resides in a DRS cluster with DPM enabled, disable DPM for that host. See the vSphere Resource Management documentation for instructions about overriding the default DPM setting for an individual host.
Verify that you know the virtual machine requirements for USB devices. See Connecting USB Devices to an ESXi Host.
Verify that the ESXi host is powered off before you add USB CD/DVD-ROM devices.
What to do next
You can now add the device to the virtual machine. See Add USB Devices from an ESXi Host to a Virtual Machine in the vSphere Web Client.