So, it is a problem when you run out of the space. Below is what I did.

gpart show
swapoff -a
gpart recover da0
gpart resize -i 3 -s 70G da0
gpart add -t freebsd-swap -l swap da0
swapon -a

Where is the space used

For example look in /var

du -a /var | sort -n -r | head -n 10