The network infrastructure plays an important role for datacenter applications. Therefore, datacenter network architectures are designed with three main goals: bandwidth, latency and reliability. This work focuses on the last goal and provides a comparative analysis of the topologies of prevalent datacenter architectures. Those architectures use a network based only on switches or a hybrid scheme of servers and switches to perform packet forwarding. We analyze failures of the main networking elements (link, server, and switch) to evaluate the tradeoffs of the different datacenter topologies. Considering only the network topology, our analysis provides a baseline study to the choice or design of a datacenter network with regard to reliability. Our results show that, as the number of failures increases, the considered hybrid topologies can substantially increase the path length, whereas servers on the switch-only topology tend to disconnect more quickly from the main network.