Contents

Storage Virtualization Overview

Core Concepts

Summary

Storage virtualization has tremendous potential for simplifying storage administration and reducing costs associated with managing diverse storage assets. The excerpt provided here provides an overview of the core concepts of virtualization.

Storage Virtualization Overview

The data storage industry is one of the most dynamic sectors in information technology today. Due largely to the introduction of high-performance networking between servers and storage assets, storage technology has undergone a rapid transformation as one innovation after another has pushed storage solutions forward. At the same time, the viability of new storage technologies is repeatedly affirmed by the rapid adoption of networked storage by virtually every large enterprise and institution. Businesses, governments, and institutions today depend on information, and information in its unrefined form as data ultimately resides somewhere on storage media. Applying new technologies to safeguard this essential data, facilitate its access, and simplify its management has readily understandable value.

Since the early 1990s, storage innovation has produced a steady stream of new technology solutions, including Fibre Channel, network-attached storage (NAS), server clustering, serverless backup, high-availability dual-pathing, point-in-time data copy (snapshots), shared tape access, storage over distance, iSCSI, CIM (common information model)-based management of storage assets and transports, and storage virtualization. Each of these successive waves of technical advance has been accompanied by disruption to previous practices, vendor contention, over-hyping of what the new solution could actually do, and confusion among customers. Ultimately, however, each step in technical development eventually settles on some useful application, and all the marketing dust finally settles back into place.

No storage networking innovation has caused more confusion in today's market, however, than storage virtualization. In brief, storage virtualization is the logical abstraction of physical storage systems and thus, when well implemented, hides the complexity of physical storage devices and their specific requirements from management view. Storage virtualization has tremendous potential for simplifying storage administration and reducing costs for managing diverse storage assets.

Unlike previous new protocols or architectures, however, storage virtualization has no standard measure defined by a reputable organization such as INCITS (InterNational Committee for Information Technology Standards) or the IETF (Internet Engineering Task Force). The closest vendor-neutral attempt to make storage virtualization concepts comprehensible has been the work of the Storage Networking Industry Association (SNIA), which has produced useful tutorial content on the various flavors of virtualization technology. Still, storage virtualization continues to play the role of elephant to the long lines of vendors and customers who, having been blinded by exaggerated marketing claims, attempt to lay hands on it in total darkness. Everyone walks away with a different impression. It is often difficult, therefore, to say exactly what the technology is or should be expected to do.

As might be expected, some of the confusion over storage virtualization is vendor-induced. Storage virtualization products vary considerably, as do their implementation methods. Vendors of storage arrays may host virtualization directly on the storage controller, while software vendors may port virtualization applications to servers

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