'Number of successful backend requests needed for the proxy to consider
the client PUT request successful.
The quorum size for EC policies defines the minimum number
of data + parity elements required to be able to guarantee
the desired fault tolerance, which is the number of data
elements supplemented by the minimum number of parity
elements required by the chosen erasure coding scheme.
For example, for Reed-Solomon, the minimum number parity
elements required is 1, and thus the quorum_size requirement
is ec_ndata + 1.
Given the number of parity elements required is not the same
for every erasure coding scheme, consult PyECLib for
min_parity_fragments_needed()'

@property
def quorum(self):

    return (self._ec_quorum_size * self.ec_duplication_factor)
