When attaching any kind of USB devices, the service
usbarbitrator claims those devices to allow passing through USB devices into virtual machines. This is (one of) the reason you won’t see USB sticks as "Storage Devices" on your ESXi, therefore not allowing you to create a datastore on it.
But at this point you have to make a decision, as you can’t have both:
- Using a USB device as a storage
- OR having the ability to passthrough USB devices to VMs
Just to be very clear: This is NOT officially supported by VMware. You should not use datastores on USB devices in production.
If you decide to go ahead…