DMDS adopts pair of system back-up and mirror-back-up memory technology. So the system has high reliability of metadata management.

具有容错能力的双元数据服务器采用双系统备份、镜像复制存储技术，从而保证了元数据管理的高可靠。

youdao

It is the mirror of the world and its memory.

UNESCO: UK National Commission for UNESCO :: Memory of the World

Behind the mirrors is a memory chip, each cell of which corresponds to one mirror.

ECONOMIST: Curtains for celluloid