':param FilePath root_path: The path beneath which all loopback backing
files and their organising directories will be created.
:param unicode compute_instance_id: An identifier to use to identify
"this" node amongst a collection of users of the same loopback
storage area.  Instances which are meant to behave as though they
are running on a separate node from each other should have
different ``compute_instance_id``.
:param int allocation_unit: The size (in bytes) that will be
reported by ``allocation_unit``. Default is ``1``.'

def __init__(self, root_path, compute_instance_id, allocation_unit=None):

    self._root_path = root_path
    self._compute_instance_id = compute_instance_id
    if (allocation_unit is None):
        allocation_unit = 1
    self._allocation_unit = allocation_unit
