VirtualBox Mac OS X 10.9: boot from an USB drive
First list all your device and identify your USB drive:
$ diskutil list
What it’s done, make sure it is not mounted:
$ diskutil unmountDisk /dev/disk2
The tricky part is that the VirtualBox process can only read/write files owned by the current user you are logged with. However Mac OS X, had put root as owner. With this default, you won’t be able to import the disk file that we are going to create. So the solution is too change the permission of the device.
$ ls -al /dev/disk2
Then create the disk file:
$ VBoxManage internalcommands createrawvmdk -filename /Users/leseb/Documents/usbdrive.vmdk -rawdisk /dev/disk2
Eventually, add the disk file in your storage manager in VirtualBox.