Cannot mount a USB key or disk device media to an ESX/ESXi host

VMware vSphere ESXi

Restart the usbarbitrator service, if you are unable to connect USB key or disk device media to an ESX/ESXi host.

Symptoms:

Connecting a USB key or disk device media to the ESXi/ESX host fails.
The USB key or disk device media appears under lsusb but does not mount correctly.

VMware vSphere ESXi 5.0
VMware ESX 4.1.x
VMware ESXi 4.1.x Installable
VMware ESXi 4.1.x Embedded
VMware vSphere ESXi 5.1
VMware vSphere ESXi 5.5

This issue occurs because the usbarbitrator service has claimed the device to make it available for passthrough to virtual machines.

Note: Ensure the USB devices are supported and compatible with ESX/ESXi host. For more information, see Supported USB device models for passthrough from an ESX or ESXi host to a virtual machine (1021345).

To resolve this issue, restart the usbarbitrator service:

Run this command to stop the usbarbitrator service:

/etc/init.d/usbarbitrator stop
Disconnect and reconnect the USB key or disk device media. The device is automatically mounted under /vmfs/volumes/NO NAME/.
After using the device, start the usbarbitrator service by running this command:

/etc/init.d/usbarbitrator start
To restore USB device access for passthrough to virtual machines without restarting, restart the hostd management service.

USB device added to ESXi host cannot be formatted with VMFS (File System). This is by design that storage stack filters USB devices when mounted.
FAT32 is unsupported file system for pass-through USB devices.

You can use the /var/log/usb.log file to view the status of USBArb with the device attached.
lsusb command can be used to list all the devices attached along with the Bus and its Device ID.

For example, the sample output looks similar to:

Bus 001 Device 002: ID 8087:800a Intel Corp

Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub