An important problem of designing distributed systems is to provide a high level of data safety. To solve this problem, two main s could be considered. The first method is to place the replicas of data files into computer network nodes. The second method is based on using a redundancy of data files’ replicas (copies and prehistory's of replicas) in the network nodes. The paper considers formal models of these two methods that are followed by a brief description of the decision-making process to ensure the preservation of data safety. This process is supported by means of an automated complex consisting of two software modules. These modules solve the problem of the optimal use of the two presented methods, ensuring the data safety in tributed systems. Finally, the application of the proposed approach in the design of logistics and transportation systems is discussed