When I installed OpenBSD on this system's 14.4 GB drive, I made the root partition a whole lot bigger than recommended. I recall a previous FreeBSD install that crapped out when I didn't have enough space, but I was too ambitious on what I was installing at that point. Still, I gave / a whole gigabyte. I'm not quite sure why I gave /usr so much space, but in the case of /, I wanted to make sure I had room to grow.