The 3-2-1 backup strategy simply states that you should have 3 copies of your data (your production data and 2 backup copies) on two different media (disk and tape) with one copy off-site for disaster recovery
3-2-1的备份策略只是指出，您应该在两个不同的媒体（磁盘和磁带）上拥有3份数据副本（您的生产数据和2份备份副本），其中一份副本副本以供灾难恢复