Storage Virtualization Architectural Approaches

Besides the fact that many storage-virtualization solutions are brand-new, another reason demand is tepid is due to limitations of the technology and the differing approaches to solving the same problem. Some cases in point: IBM's SAN Virtual Controller appliance runs on its xSeries platform, connecting the arrays to the storage switch. EMC's Invista, by comparison, runs in a customer's choice of SAN fabric switches, while Veritas touts a pure software-based approach. While customers ponder the various architectural approaches, interoperability between different vendors is also still a work in progress. The Storage Networking Industry Association is trying to come up with a standard API that will let different virtualization engines interconnect with one another and among the different switches. Although vendors say customers can upgrade the code of their systems once the standard, called FAIS, is agreed on--observers say that likely will be some time in 2006--others maintain that customers would rather wait for demonstrable compatibility, at least before virtualizing storage of production data, particularly among different vendors' systems.