استوریج Tier بندی شده Storage Tiering

Tiered storage is the assignment of different categories of data to different types of storage media in order to reduce total storage cost. Categories may be based on levels of protection needed, performance requirements, frequency of use, and other considerations. Since assigning data to particular media may be an ongoing and complex activity, some vendors provide software for automatically managing the process based on a company-defined policy.

As an example of tiered storage, tier 1 data (such as mission-critical, recently accessed, or top secret files) might be stored on expensive and high-quality media such as double-parity RAIDs (redundant arrays of independent disks). Tier 2 data (such as financial, seldom-used, or classified files) might be stored on less expensive media in conventional storage area networks (SANs). As the tier number increased, cheaper media could be used. Thus, tier 3 in a 3-tier system might contain event-driven, rarely used, or unclassified files on recordable compact discs (CD-Rs) or tapes.

Tiered storage is an underlying principle of ILM (informationlifecycle management). It is a storage networking method wheredata 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.

Implementing tiered storage infrastructures can dramatically decrease the cost associated with achieving anRPO and RTO of zero. Classification of data can provide different RPOs and RTOs based on application and business requirements.  Policy-based data migration ensures that the right data is in the right place at the right time.

Learn more about storage networking on Enterprise Storage Forum.