Tiered storage is an underlying principle of ILM (information lifecycle management). It is a storage networking method where data is stored on various types of media based on performance, availability and recovery requirements. For example, data intended for restoration in the event of data loss or corruption could be stored locally — for fast recovery — while data for regulatory purposes could be archived to lower cost disks.
Today’s tiered storage infrastructures range from simple two-tier architecture consisting of SCSI or fibre channel attached disk and tape to more complex infrastructures, which in some cases are comprised of five-to-six tiers. Regardless of the number of tiers, organizations are looking to tiered storage and ILM to lower cost and improve operational efficiency.