参考文档：
https://www.howtoing.com/create-raid1-in-linux
https://blog.51cto.com/13659182/2109197
https://www.cnblogs.com/liuhui-xzz/p/9655158.html
https://blog.51cto.com/14157628/2415484
https://www.cnblogs.com/liuhui-xzz/p/11638167.html
Raid1操作命令（软Raid）
//安装mdadm工具
yum install mdadm