Without any doubt, technical characteristics and performance of FC disks remain for nowsuperior to those of SATA disks. However, not all storage applications require the superiorfeatures of Fibre Channel. When used for the appropriate enterprise applications, SATA disksoffers a tremendous cost advantage over FC. First, SATA drives are cheaper to manufactureand because of their larger individual capacity, SATA drives are on average sixty percentcheaper per gigabyte than FC disks. The fact is that in large capacity systems, the drivesthemselves account for the vast majority of the cost of the system. Using SATA disks willsubstantially reduce the TCO of the storage system.
Storage data can reside at three different locations within the network storage hierarchy. Thisis also known as tiered storage, shown in Figure below.
Particular data types are suitable for storage at the various levels.
1) Online (primary) storage
Best suited for business critical applications that require constant instantaneous access todata, such as databases and frequently accessed user data. This data requirescontinuous availability and typically has high performance requirements. Business-criticaldata will be stored on Fibre Channel disk implemented in enterprise-class storagesolutions.
2) Near-Line (secondary) storage
Used for business important applications that require quicker access compared with offlinestorage (as tape), but do not require the continuous, instantaneous access provided byonline storage. Secondary storage represents a large percentage of a company’s data andis an ideal fit for SATA technology.
3) Offline (archival) storage
Used for applications where infrequent serial access is required, such as backup forlong-term storage. For this type of storage, tape remains the most economical solution.
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