VirtualBox Raw Hard Disk Access
There are multiple methods of accessing the data on a hard drive from within virtual environments. One option is to use the contents of a physical drive to create a virtual hard disk image. At times, it may be more beneficial to mount or boot a physical hard drive directly from a guest VM.
VirtualBox enables you to mount all or part of a hard drive. You can designate specific partitions to be mounted or choose to use the complete disk. We will be discussing the method known as VirtualBox raw hard disk access. This is where the whole VirtualBox physical hard drive is mounted. The advantages of this method include giving users the ability to boot their system from an external USB drive or additional hard disk.
We will demonstrate how to accomplish this on Windows, Mac OS X, and Linux host operating systems.
Note: You should always backup your data before attempting to mount drives or partitions in your virtual machine. Avoid mounting or booting the partition running the host operating system, as it may result in substantial data corruption.
- The first step is to use the VirtualBox user interface to create a virtual machine. Use your regular configuration except for the selection of a virtual hard drive. Choose the “Do not add a virtual hard drive” option.
- You will need to identify the drive number and path of the physical drive you intend to mount. Use the appropriate method for your host operating system.
Windows: Open Disk Management where the drive numbers will be displayed on the left side. They will be identified as PhysicalDrive0, PhysicalDrive1, etc.
Mac OS X: Enter the “diskutil list” command which returns a list of the available disk partitions. The drive names will be displayed in the format /dev/disk0, /dev/disk1, and so on.
Linux: To list the partitions in Linux, the “sudo fdisk -l” command is used. The format for disks in Linux is dev/sda0, dev/sda1, etc.
- Once you have obtained the drive number, you are ready to open the CLI of your operating system. When Windows is the host OS, you need to navigate to VirtualBox’s root directory. Use this command:
“cd C:\Program Files\Oracle\VirtualBox”.
- At this point, you are ready to create a virtual hard drive file from the contents of the physical device. The generic commands below require you to use the name and number of your drive where appropriate.
For Windows: VBoxManage internalcommands createrawvmdk -filename "C:\Users\<user_name>\VirtualBox VMs\<VM_folder_name>file_name.vmdk" -rawdisk \\.\PhysicalDrive#
For Mac OS X: VBoxManage internalcommands createrawvmdk -filename "</path/to/file>.vmdk" -rawdisk /dev/disk#
For Linux: VBoxManage internalcommands createrawvmdk -filename "</path/to/file>.vmdk" -rawdisk /dev/sda
The VMDK that is created is a small file that acts as a pointer to the physical hard drive. To use the disk, you just attach the VMDK to your virtual machine. Perform the following steps after opening to VirtualBox GUI.
- Select the desired virtual machine that will access the disk.
- Click “Settings > Storage > Add Hard Disk”.
- Select the “Choose existing drive” option.
- Choose the VMDK file previously created.
Your virtual machine can now boot from the physical drive associated with the VMDK file.
