The "Use an entire disk" option installs Ubuntu onto the selected disk,
replacing any partitions and data already there.
If the platform requires it, a bootloader partition is created on the disk.
If you choose to use LVM, two additional partitions are then created,
one for /boot and one covering the rest of the disk. An LVM volume
group is created containing the large partition. A logical volume is
created for the root filesystem, sized using some simple heuristic. It
can easily be enlarged with standard LVM command line tools (or on the
next screen).
You can also choose to encrypt LVM volume group. This will require
setting a passphrase, that one will need to type on every boot before
the system boots.
If you do not choose to use LVM, a single partition is created covering the
rest of the disk which is then formatted as ext4 and mounted at /.
In either case, you will still have a chance to review and modify the results.
If you choose to use a custom storage layout, no changes are made to the disks
and you will have to, at a minimum, select a boot disk and mount a filesystem
at /.
