This paper describes the configuration of a power-saving and high-availability server system achieved by the compound operation of a power-saving server system (PSS) and a multiple-server backup system (MSBS) that can operate independently. The PSS shifts the system configuration to either a normal condition or a power-saving condition according to server loads. In the power-saving condition, the proposed method has two server configurations. In the first, the servers providing services to clients are configured redundantly, and in the second they are not. Furthermore, a dynamic server recovery system that manages real servers is proposed in addition to a dynamic backup server system (DBSS) that manages a virtual server in the MSBS. Therefore, if real servers have trouble, recovery operations are automatic and prevent access disruption for the client. In the compound operation, the MSBS needs status information on configuration changes in the server system made by the PSS, and the PSS needs to execute the DBSS during the configuration change. Thus, a system interface, which has the functions of bi-directional control of the PSS and MSBS, is proposed to enhance the functions of the management program in the PSS and MSBS. In addition, an experimental server system incorporating the proposed method was constructed. In the power-saving condition, the proposed system operated at 70% of power consumption of the normal condition when virtual servers were configured redundantly, and operated at 40% when a non-redundant configuration was used. Experiments were conducted to reproduce several types of trouble in the virtual server or the real server in a server configuration under both normal and power-saving conditions. The proposed system is shown to have high availability in either condition.