In the 1990’s, when direct-attached storage (DAS) was the prevalent mode of file storage, network-attached storage (NAS) was introduced to support file sharing across enterprise networks. Vendors merged Sun Microsystems’ open source NFS protocol and NFS file server with Microsoft’s CIFS (Common Internet File Service) protocol on common platforms and NAS quickly became a staple of enterprise environments.
Yet as simple as file-level storage is, many businesses and organization also need the performance and versatility of block-level storage and, hence, rely on Fibre Channel storage area networks (SANs). Fibre Channel (FC) is costly technology, however, and in 2003, the IP-based iSCSI standard was ratified as a low cost solution for linking storage devices. iSCSI NAS is certainly an attractive strategy, but many enterprises have substantial investments in their FC SAN environments. Maintaining separate boxes for file-based iSCSI and block-based FC is expensive and inefficient, especially when IT staffs are stretched thin.
As a remedy, NAS vendors integrated iSCSI and native FC protocols into their NAS storage solutions. By combining multiple protocols on the same platform, the term unified storage emerged in the IT lexicon. A single device could serve as file storage, block storage, or both simultaneously. The advantages were many. Making do with one box rather than two reduces capital expenditures, economizes on operating costs like power and cooling, and simplifies management. When the physical device is a robust RAID array, unified storage also delivers high performance, scalability, data protection, and reliability. As a result, unified storage, which was initially viewed as a tier 2 storage solution, is becoming a viable alternative to SANs. In a time when companies must do more with less, unified storage is a practical strategy for meeting the storage needs of many small- and mid-sized enterprises.