Tiered storage offers reduced data storage costs, higher efficiency and the ability to reuse older equipment
"Tiered storage is a storage method which involves storing data on a range of different storage media with different characteristics, such as performance, cost, and capacity.
The different storage media are organized into a hierarchy, where the highest performance storage media is deemed to be Tier 0 or Tier 1, followed by Tier 2, Tier 3, and so on.
Tier 0 or Tier 1 is usually made up of flash or 3D XPoint-based solid state drives, while successive tiered storage levels may involve high performance fibre channel or SAS drives (or RAID arrays containing them), lower performance SATA drives, optical disks, tape storage systems, and cloud-based nearline or offline storage systems..." - Oracle News
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