Create Hard Disk for VM
4. Next, you must specify a virtual hard disk for your VM.
There are many and potentially complicated ways in which VirtualBox can provide hard
disk space to a VM (see chapter 5, Virtual storage, page 74 for details), but the most
common way is to use a large image file on your ârealâ hard disk, whose contents VirtualBox
presents to your VM as if it were a complete hard disk. This file represents an entire hard
disk then, so you can even copy it to another host and use it with another VirtualBox
installation.
The wizard shows you the following window:
Here you have the following options:
1 First steps
To create a new, empty virtual hard disk, press the âNewâ button.
You can pick an existing disk image file.
The drop-down list presented in the window contains all disk images which are currently
remembered by VirtualBox, probably because they are currently attached to a
virtual machine (or have been in the past).
Alternatively, you can click on the small folder button next to the drop-down list to
bring up a standard file dialog, which allows you to pick any disk image file on your
host disk.
Most probably, if you are using VirtualBox for the first time, you will want to create a new
disk image. Hence, press the âNewâ button.
This brings up another window, the âCreate New Virtual Disk Wizardâ, which helps you
create a new disk image file in the new virtual machineâs folder.
VirtualBox supports two types of image files:
A dynamically allocated file will only grow in size when the guest actually stores
data on its virtual hard disk. It will therefore initially be small on the host hard drive
and only later grow to the size specified as it is filled with data.
A fixed-size file will immediately occupy the file specified, even if only a fraction of
the virtual hard disk space is actually in use. While occupying much more space, a
fixed-size file incurs less overhead and is therefore slightly faster than a dynamically
allocated file.
For details about the differences, please refer to chapter 5.2, Disk image files (VDI, VMDK,
VHD, HDD), page 76.
To prevent your physical hard disk from running full, VirtualBox limits the size of the image
file. Still, it needs to be large enough to hold the contents of your operating system and the
applications you want to install â for a modern Windows or Linux guest, you will probably
need several gigabytes for any serious use:
After having selected or created your image file, again press âNextâ to go to the next page.
5. After clicking on âFinishâ, your new virtual machine will be created. You will then see it
in the list on the left side of the Manager window, with the name you entered initially.
