Network function virtualization (NFV) is a promising technique aimed at reducing capital expenditures (CAPEX) and operating expenditures (OPEX), and improving the flexibility and scalability of an entire network. In contrast to traditional dispatching, NFV can separate network functions from proprietary infrastructure and gather these functions into a resource pool that can efficiently modify and adjust service function chains (SFCs). However, this emerging technique has some challenges. A major problem is reliability, which involves ensuring the availability of deployed SFCs, namely, the probability of successfully chaining a series of virtual network functions while considering both the feasibility and the specific requirements of clients, because the substrate network remains vulnerable to earthquakes, floods, and other natural disasters. Based on the premise of users' demands for SFC requirements, we present an ensure reliability cost saving algorithm to reduce the CAPEX and OPEX of telecommunication service providers by reducing the reliability of the SFC deployments. The results of extensive experiments indicate that the proposed algorithms perform efficiently in terms of the blocking ratio, resource consumption, time consumption, and the first block. © 2013 IEEE.