I run a small HP T730+ as a backup "server" in my home and to accomplish this I run a few VMs to keep my network running if my server shut downs. I also utilize this as my main DSM's backup for personal files/VMs. Due to the 730+ not having any SATA ports I'm forced to run a USB to SATA adapter for the backup drive; a WD 4TB. To avoid DSM filesystem obfuscation by mounting and writing inside a VMDK and also avoid issues with ESXi and USB drives >2TB, I wanted to pass the USB SATA controller through to DSM. However, the "./rploader.sh identifyusb" command blocks USB if it detects you are using VMWare as a hypervisor.
If you are running ESXi and want to pass through a USB harddrive you will need to edit your VM to passthru the USB device your drive is on and then go into the rploader.sh file and comment out the following lines (put a # in front of them) to avoid the script ending the usbidentify routine when it detects your hypervisor:
if [ "$MACHINE" = "VIRTUAL" ] && [ "$HYPERVISOR" = "VMware" ]; then
echo "Running on VMware, no need to set USB VID and PID, you should SATA shim instead"
exit 0
fi
Once this is done you can run the identifyusb option and have it assign a PID/VIN to your USB drive and after building, your drive should show up as an external device in DSM.
Also of note, my network transfers during a HyperBackup task have doubled over the rates seen when the VM was writing to a VMDK file located on the USB drive.