Tiered Storage

• tiered storage

Tiered storage is a way to assign different categories of data to various types of storage media with the objective of reducing the total cost of storage.
A tiered storage architecture places data in a hierarchy according to its business value.
Tiers are determined by performance and cost of the media, and data is ranked by how often users access it.

Tier 1 storage
Tier 1 data includes mission-critical applications, recently accessed data or top-secret files. This data might be stored on expensive, high-quality media, such as double-parity RAID.

Tier 2 and Tier 3 storage
Even as primary operations are being completed, Tier 1 data is usually written simultaneously to a secondary tier of disk-based backup appliances or to magnetic tape. Data centers deploy a backup tier to aid business continuity and disaster recovery (BC/DR) through fast restores of key files and storage hardware.
Data on Tier 2 storage usually contains historical financial information, cold data and classified files. This data is preserved on lower-cost media in a conventional storage area network (SAN)

Tiering vs. caching
Storage tiering and caching technologies are often used interchangeably -- especially when dealing with flash media -- but they are different processes. Tiered data resides on one media type at any time but moves between media as data access patterns change.

https://searchstorage.techtarget.com/definition/tiered-storage

• Flexible Storage Throughout the Data Lifecycle

add-on feature lets you store and manage data in different tiers based on cost and performance trade-offs—whether it’s flash storage, traditional local or shared disk storage, HDFS, or Amazon cloud storage. With Tiered Storage, your data is easily migrated between tiers without any ETL, additional software, or expensive infrastructure changes. This allows you to easily balance performance and capacity through the lifecycle of your data—meeting performance SLAs, making data governance easier, and meeting compliance requirements.

https://www.marklogic.com/product/marklogic-database-overview/database-features/tiered-storage/