Mountpoints

zfs set mountpoint=none backupool
zfs set mountpoint=none backupool/BACKUP
zfs set mountpoint=/BACKUP backupool/BACKUP

sudo zfs allow -u USER create,mount,destroy,refreservation pool/path/to/prj
 
# list permissions
zfs allow pool/path/to/prj

When a pool is created, the pool is intrinsically tied to the host system. The host system maintains knowledge about the pool so that it can detect when the pool is otherwise unavailable. While useful for normal operation, this knowledge can prove a hindrance when booting from alternate media, or creating a pool on removable media. To solve this problem, ZFS provides an alternate root pool feature. An alternate root pool does not persist across system reboots, and all mount points are modified to be relative to the root of the pool. 

To change alternate root runtime:

zpool export backuppool
zpool import -R /fakeroot backuppool 

To remove alterante root:

zpool export backuppool
zpool import backuppool