Storage Tiering Options - Page 2
Within a Storage System
Storage tiering does not only cover moving data from one storage system to another. Storage tiering may also refer to dynamic data movement within a single storage system based on application performance needs. In this case, storage tiering is primarily concerned with accelerating data performance within the production storage system, and secondarily storing aging production data on less-expensive tiers within the array, or storing snapshots on cheap storage.
This technology tiers data within a multi-tiered single storage system or between connected single-vendor systems. The most common configuration is a hybrid storage system where the automated tiering function stores high priority workloads on a flash layer, then moves them to hard disk tiers. In reality, this process may also occur on all-flash arrays or on hybrid arrays where there are two classes of flash that exist in front of the hard drives.
Dynamic automated tiering within the system is a hallmark of Dell Storage Center. SC Series Volume Advisor proactively monitors data placement and storage optimization throughout all connected SC systems. Flash systems with high performance tier 0 and automated tiering services include IBM hybrid Storwize systems with Easy Tier. Easy Tier analyzes real-time usage analysis patterns and assigns data to different Storwize tiers.
This is the process of tiering storage across different classes of storage systems. In the recent past, it was common to have a three-, four-, or even five-stage tiering infrastructure consisting of a high-performance array, a nearline disk drive and tape. This is still a common solution because it works and because there is a large existing investment.
However, given large rates of data growth and rising storage expenditures, tiering choices across the infrastructure have become far more complicated than they used to be. There is still a minimal two-stack core in every infrastructure tiering configuration, which is primary storage to tape or cloud. A three-stack core is probably more common but may not be the traditional one of primary storage system, nearline disk and tape.
Today the three-stack core may consist of a flash tier and a hard drive tier on a single production system, an active archiving tier on disk or high performance tape library, and a long-term data retention tier on tape or in the cloud. Even within this updated configuration there will be alternate architectures. For example, your top production tier may be an AFA with a Tier 0 high-performance flash layer and software that dynamically tiers data between Tier 0 and Tier 1 SSD drives. Or you might have a hybrid flash system with Tier 0 and Tier 1 flash layers, and internal hard drives classified as nearline Tier 2.
There are additional options for a nearline Tier 2. A high-performance tape library may act as a nearline storage system for active archiving. So might a cloud-based tier that is engineered as a Tier 2 with fast recovery options and additional data services. Microsoft Azure StorSimple, for example, integrates on-premise appliances with a fully active cloud tier containing data services and failover functionality.
Both tape and cloud may serve as Tier 3 or 4 cool or cold storage. Major public cloud offerings for long-term data retention include Google Nearline for long-term storage with reasonable recovery times, and cold storage Amazon Glacier, which has recovery options but is geared towards retaining data with no need of regular recovery.
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