  The Bose glass (BG) phase is the Griffiths region of the disordered Bose
Hubbard model (BHM), characterized by finite, quasi-superfluid clusters within
a Mott insulating background. We propose to utilize this characterization to
identify the complete zero-temperature phase diagram of the disordered BHM in
$d\ge2$ dimensions by analyzing the geometric properties of what we call
superfluid (SF) clusters, which are defined to be clusters of sites with
non-integer expectation values for the local boson occupation number. The Mott
insulator (MI) phase then is the region in the phase diagram where no SF
clusters exist, and the SF phase the region, where SF clusters percolate - the
BG phase is in between: SF clusters exist, but do not percolate. This
definition is particularly useful in the context of local mean field (LMF, or
Gutzwiller-Ansatz) calculations, where we show that an identification of the
phases on the basis of global quantities like the averaged SF order parameter
and the compressibility are misleading. We apply the SF cluster analysis to the
LMF ground states of the two dimensional disordered BHM to produce its phase
diagram and find a) an excellent agreement with the phase diagram predicted on
the basis of quantum Monte Carlo simulations for the commensurate density
$n=1$, and b) large differences to stochastic mean field and other mean field
predictions for fixed disorder strength. The relation of the percolation
transition of the SF clusters with the onset of non-vanishing SF stiffness
indicating the BG to SF transition is discussed.
