Because there are problems with the existing structure in fixed scale, unextended performance and insufficient flexibility, the system is difficult to meet the demand of massive storage, distributed redundancy and scale dynamic adjustment. 系统现有架构存在规模相对固定、性能难以扩展、灵活性不足的缺点,难以满足海量存储、分布式冗余备份、规模动态调整等需求。