copies=1 | 2 | 3
    Controls the number of copies of data stored for this dataset. These copies are in
    addition to any redundancy provided by the pool, for example, mirroring or RAID-Z.
    The copies are stored on different disks, if possible. The space used by multiple
    copies is charged to the associated file and dataset, changing the used property
    and counting against quotas and reservations.