which filesytems zfs needs to function

[Edward M]

Hi,

I was running FreeBSD 9.0 using ZFS with the following setup on one 
harddrive:
*(5) Create appropriate filesystems (feel free to improvise!).*

zfs create zroot/usr
zfs create zroot/usr/home
zfs create zroot/var
zfs create-o  compression=on-o  exec=on-o  setuid=off zroot/tmp
zfs create-o  compression=lzjb-o  setuid=off zroot/usr/ports
zfs create-o  compression=off-o  exec=off-o  setuid=off zroot/usr/ports/distfiles
zfs create-o  compression=off-o  exec=off-o  setuid=off zroot/usr/ports/packages
zfs create-o  compression=lzjb-o  exec=off-o  setuid=off zroot/usr/src
zfs create-o  compression=lzjb-o  exec=off-o  setuid=off zroot/var/crash
zfs create-o  exec=off-o  setuid=off zroot/var/db
zfs create-o  compression=lzjb-o  exec=on-o  setuid=off zroot/var/db/pkg
zfs create-o  exec=off-o  setuid=off zroot/var/empty
zfs create-o  compression=lzjb-o  exec=off-o  setuid=off zroot/var/log
zfs create-o  compression=gzip  -o  exec=off-o  setuid=off zroot/var/mail
zfs create-o  exec=off-o  setuid=off zroot/var/run
zfs create-o  compression=lzjb-o  exec=on-o  setuid=off zroot/var/tmp

from:
http://www.aisecure.net/2012/01/16/rootzfs/





However I decided to reinstall FreeBSD such for thisparticular reason:-)
to see if is possible to create lessfilesystems, if so, which ones
in order for zfs to work properly or are the ones mention up above required,  even though it says feel free to improvise?


Hope gave all needed info:-)