  Redundancy mechanisms such as triple modular redundancy protect
safety-critical components by replication and thus improve systems fault
tolerance. However, the gained fault tolerance comes along with costs to be
invested, e.g., increasing execution time, energy consumption, or packaging
size, for which constraints have to be obeyed during system design. This turns
the question of finding suitable combinations of components to be protected
into a challenging task as the number of possible protection combinations grows
exponentially in the number of components. We propose family-based approaches
to tackle the combinatorial blowup in redundancy systems modeling and analysis
phases. Based on systems designed in SIMULINK we show how to obtain models that
include all possible protection combinations and present a tool chain that,
given a probabilistic error model, generates discrete Markov chain families.
Using symbolic techniques that enable concise family representation and
analysis, we show how SIMULINK models of realistic size can be protected and
analyzed with a single family-based analysis run while a one-by-one analysis of
each protection combination would clearly exceed any realistic time
constraints.
