双机热备这一概念有两种不太相同的意义：从广义上来说也称为双机互备，指的是对于重要的服务，使用两台服务器协同工作，共同执行同一个服务。当一台服务器出现故障时，可以由另一台服务器暂时相应原有的两个机器的所有服务，等待故障机的恢复和重新加入集群，从而在不需要人工干预的情况下，自动保证系统能持续提供服务。这种集群一般被称为高性能集群（High performance cluster. HPC）-Hot Standby two less the same meaning of the concept: Broadly speaking, also known as the Dual Active important service, use two servers work together to jointly perform the same services. When a server fails, another server may be temporarily corresponding original two machines all services, waiting for the recovery of the fault plane and re-join the cluster, which in the case without human intervention, the system can automatically guarantee continue to provide services. Such a cluster is generally referred to as high-performance cluster (High performance cluster HPC)