13.4 Convergence

The emergence of IP-based SANs, storage virtualization, InfiniBand, and hybrid NAS/SAN technologies has further complicated the SAN landscape. Just as Fibre Channel SANs are becoming lucrative, stable, and somewhat interoperable, new components are being thrown in that undermine the steady production and sale of prepackaged SAN solutions. Now storage vendors and solutions providers must create and qualify additional solutions that accommodate the advances introduced by new storage technologies.

The Fibre Channel fundamentalists advocate a straightforward approach to this problem: to simply declare that Fibre Channel is the one true SAN that will reign forever and forever. The remainder of the storage networking community, however, is not as devout, as shown by the introduction of iSCSI interfaces on enterprise-class storage arrays, multiprotocol SAN switches that support both Fibre Channel and IP, the support of SCSI block access by traditional NAS vendors, and support of file and NAS access by traditional RAID array vendors. This adaptive radiation of products promotes vendors' survival in the market by accommodating the diverse needs of customers, as opposed to bending customers around a specific architecture.

Because storage networking is itself a convergence of highly dissimilar storage and networking technologies, it is not surprising that further permutations will occur until a level of synthesis is reached. For operating systems, convergence is appearing in the form of integrated support for storage networking, as shown by support for dual pathing, virtualization, backup, and iSCSI in Windows .NET. For applications, convergence is appearing in a tighter linkage between upper-layer applications and application-aware intelligence in the SAN. For the interconnection, convergence is surfacing as multiprotocol SAN switches and SAN internetworking, as well as integrated interfaces for new InfiniBand clusters. For storage targets, concurrent support for multiple interfaces and protocols as well as virtualization intelligence enables customers to select a single product that can adapt to changing requirements.

Convergence is a transitional state. At some point, the convergence process in storage networking will generate a new, uniform architecture based on the best traits of its contributing technologies, just as on a larger scale the Internet has emerged as a distinct entity, far greater than the sum of its parts.

Although the ongoing convergence of storage networking technologies has its own noise and confusion factor, it is creating new options for customers and is broadening the market opportunity for vendors. More rigor on the standards, interoperability, and management fronts will help to remove the remaining obstacles to SAN adoption, and convergence will facilitate productive deployment of SANs for enterprises and small businesses alike.