While performing some experiments in my home lab, I needed to access a USB storage key directly on my ESXi host (not pass-through to VMs) and found it required a small trick after some tinkering. I thought I share the process in case this comes in handy for others.
Disclaimer: This is mainly for educational and testing purposes as this is not officially supported by VMware. Please use at your own risk.
Before I begin, you should know that only USB storage devices formatted with FAT16 can be accessed in the ESXi shell and is applicable to both ESXi 4.1 and 5.0.
Step 1 - Login to ESXi Shell via SSH and disable the USB Arbitrator service (this is automatically enabled by default to allow pass-through of USB devices to your VMs) using the following command: /etc/init.d/usbarbitrator stop
Step 2 - Plug-in your USB device to your ESXi host and you can verify by using the two ESXCLI commands: verifying the storage device using the command: esxcli storage core device list | grep -i usb or viewing the mounted filesystems using the command: esxcli storage filesystem list
Step 3 - Lastly, after you verify the USB device can be seen by the ESXi host, you can of course browse and access your USB device by looking under /vmfs/volumes/
Te re-enable pass-through of USB devices to your VMs, you just need to start the usbarbitrator service.