By grouping homogeneous storage media in tiers, companies can store data more efficiently -- for example, maintaining frequently accessed transactional records on the fastest devices and moving older or seldom accessed files to a less expensive tier. As such, tiered storage provides obvious financial benefits, reducing the average cost of data that is parked for longer periods of time and rarely referenced, if at all.
And when it comes to seldom accessed data, the lower acquisition price of SATA systems can be reason enough to move to a tiered storage architecture. According to a recent IDG study, the cost per gigabyte of "capacity optimized" systems is less than half that of "performance optimized" systems, a ratio that seems likely to extend into the future.
Though the cost gap between systems can be even greater than those worldwide averages, acquisition savings are not the only benefits of tiered storage. Purchasing dense devices, for example, can avoid or delay capital expenditures to extend the datacenter.
Although difficult to put a dollar value on, isolating critical tier-1 data from the crowd of less sensitive data is the first step in establishing a more business-conscious storage environment -- likely the most desirable aspect of employing a tiered storage strategy in the enterprise.
In fact, some vendors are now offering "tier 0" devices to create a very fast, memory-based buffer between servers and conventional, disk-based storage. Not to be confused with traditional cache memory, which is either embedded within the application server or the storage device, these tier-0 devices are SSDs (solid state drives) that are fed with or deprived of data to improve the response time of the storage system.
Xiotech, for example, recently announced SSDs for its Magnitude 3D 3000 SAN systems. Gear6, a startup recently out of stealth mode, has customers tapping its CacheFX, a RAM-based NFS accelerator.
Obviously, such implementations target a different objective than traditional tiered storage does -- namely, creating a top performing layer of storage, rather than reducing cost. However, even if more expensive, tier-0 solutions respond to the same optimization criteria that suggest moving your data from enterprise storage to high-capacity SATA drives and eventually to tape. Managing those data allocations efficiently is the new challenge that storage admins face.
Read more about storage in InfoWorld's Storage Channel.