The Importance Of Storage Domain management - Technology Information

Computer Technology Review, Oct, 1999 by Eric Burgener

In today's fast paced world, the changing nature of business has significant implications for the design and deployment of Information Technology (IT) infrastructure. While executive management grapples with adapting the organization to the new business environment, IT is expected to evolve as well, providing the supporting infrastructure necessary to attain business goals. With the growth of the Internet and the emergence of e-commerce as a powerful force across all industries, IT infrastructure decisions play an increasing role in achieving business success. Traditional IT architectures and management paradigms are in many cases proving themselves unable to provide the required flexibility. Characteristics of the new business environment include:

* Rapid, unpredictable change

* Unexpected business obstacles and opportunities

* Significantly condensed business life cycles

* Data as a key enabler of business success

The impact of the new environment on IT, and in particular storage, has been profound. There has been an explosion in the growth of storage, driven in large part by the increasing importance of data to competitive advantage. Access to this data, in fact, often drives competitive advantage. The traditional "direct attach" storage architecture lacks the flexibility to provide high-speed access from multiple servers to essential data amidst rapid, unpredictable change. The escalating costs of the traditional model and, in particular, the management costs associated with that storage have led to a low perceived value for investments made. Storage asset utilization is often sub-optimal. Clearly, the traditional storage architecture is not meeting the requirements of the new business climate.

THE EMERGENCE OF STORAGE AREA NETWORKING

Storage Area Networking (SAN) is a new storage-centric computing architecture that has emerged over the last 18 to 24 months to better enable the IT flexibility demanded by a much faster-paced business climate. Driven in large part by the availability of Fibre Channel-based storage subsystems and network components, SANs promise high speed data access and movement, more flexible physical configuration, improved utilization of storage capacity, centralized storage management, online storage resource deployment and reconfiguration, and support for heterogeneous environments.

In the older "direct attach storage" model, storage resources had a high-speed direct physical path to only a single server. All other servers had much lower speed access to that storage resource only indirectly through the LAN. Storage area networks change that by providing direct, high-speed access paths (through Fibre Channel) from every server to every storage resource in a "networked" topology. The introduction of a network architecture also significantly improves storage configuration flexibility, de-coupling storage resources from a particular server, and potentially allowing them to be managed or configured with minimal impact on server-side resources (Fig 1).

ACHIEVING THE PROMISE OF SANS

The high speed, "any to any" connectivity of the SAN architecture offers significant promise in resolving many of the issues plaguing enterprise storage environments today. Despite their broad potential, practical interoperability issues have kept most SANs relatively small and homogeneous in nature and have limited most deployments to pure connectivity solutions (storage consolidation) or simple storage resource sharing (SAN-based backup). Architecturally, the true promise of SANs is to leverage a consistent set of rich storage management functions across a large number of consolidated heterogeneous server and storage resources that are managed through a single interface and all connected at high speeds through a dedicated storage network. Merely providing the physical connections between servers and storage resources through SAN fabric components such as switches, hubs, or routers is not sufficient to achieve this promise. Significant storage management intelligence is also required to harness the natural a dvantages of this storage-centric architecture against today's most difficult storage management problems.

A critical issue in SAN architecture and design is the location of this storage management intelligence. Traditionally, storage management intelligence has resided in server-based components, but with the rise of intelligent disk subsystems more and more of this management capability has migrated out to the storage resources. Either of these approaches can be reasonably applied to homogeneous environments that have relatively few attached resources (servers, storage), but they quickly become sub-optimal and cost-inefficient in heterogeneous environments requiring higher levels of connectivity. High rates of storage growth are driving businesses to consider consolidation to improve storage management and consolidation of existing resources makes heterogeneous environments almost inescapable. Consolidation will bring products from a variety of different server and storage vendors into a single SAN environment. The dynamics of today's business environment will drive customers to large, heterogeneous SANs--a mode l in which server or storage resource-based storage management intelligence will be sub-optimal.