In this article, we propose an approach to build fault-tolerant distributed real-time embedded systems. From a given system description and a given fault hypothesis, we generate automatically a fault tolerant distributed schedule that achieves low energy consumption and high reliability efficiency. Our scheduling algorithm is dedicated to multi-bus heterogeneous architectures with multiple processors linked by several shared buses, which take as input a given system description and a given fault hypothesis. It is based on active redundancy to mask a fixed number L of processor failures supported in the system, and passive redundancy based on variable data fragmentation to tolerate N buses failures. In order to maximize the systems reliability, the replicas of each operation are scheduled on different reliable processors and the size of each fragmented data depends on GSFR and the bus failure rates. Finally, we show with an example that our approach can maximize reliability and reduce energy consumption when using active redundancy.