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
A research study from Evaluator Group guides users through the maze of approaches and issues they will encounter when evaluating storage as a service (STaaS)
"It also offers a window into mixed and sometimes conflicting user perceptions; highlighting the potential motivations for deploying STaaS, while pointing out the reasons why users may have misgivings.
Study of Enterprise User Perceptions and Requirements
Potential enterprise end users of STaaS commonly equate it to public cloud storage. Cloud storage is available, offers unlimited capacity, and the ability to spin up/down resources using only what you pay for-all available as a pay-as-you go, managed resource. This has made it a ready alternative to traditional storage..." - Storage Newsletter