The default partitioning (the one obtained by pressing
<keycap>A
</keycap> at the FreeBSD partition editor, called
<application>Disklabel
</application>) does not leave any unallocated space. Each partition that will be journaled, requires another partition for the journal. Since the
<filename>/usr
</filename> partition is the largest, it makes sense to shrink this partition slightly, to obtain the space required for journaling.