The movement of data from fast-access storage ( magnetic disc ) to storage of lower access speed ( magnetic tape ).

数据由快速存取存储器（磁盘）传送到存取速度较低的存储器（磁带）的过程。

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Yet most companies treat all of their data as if it were created equal, storing it on fast, expensive storage as if every bit requires frequent, rapid access.

FORBES: As Corporate Data Grows, Costs Don't Have To

These issues, plus the fact that mobile devices are sometimes not able to connect and access content in the cloud, is feeding the already fast growing external storage device market.

FORBES: Changing Digital Storage Requirements for Clouds and Mobile Devices

In addition, the Drobo 5N, much like its sibling Thunderbolt-powered solutions the Drobo Mini and 5D, utilizes Drobo's Data-Aware Tiering capability, which intelligently uses high-performance flash (SSD) technology to accelerate performance of the storage array, allowing applications such as Adobe Lightroom and Apple iPhoto or iTunes fast access to data.

ENGADGET: Drobo's new 5N is a speedy $600 NAS for when you need files, stat