Failures in databases other than the mirrored database are not detectable in a database mirroring session . moreover , a data disk failure is unlikely to be detected , unless the database is restarted because of a data disk failure 由于网络会指示任何两个服务器实例之间的连接断开的时间,因此,数据库镜像会话中的每个服务器实例都会在另外一个服务器实例断开连接时立即受到警告。