No quick virtualization fixes: achieve the goals of virtualization through holistic storage management.

Not very long ago, IT managers considered virtualization as the leading candidate to deliver the long-sought solution to their storage problems. Virtualization would enable them to easily pool all their disparate storage scattered across the organization's heterogeneous IT environment. It would allow them to carve up and allocate that storage as needed and effectively utilize all the storage capacity they owned. And when things changed, they could repurpose and reallocate that storage on the fly without disrupting the users and applications that relied on the storage.

Many storage industry vendors promised virtualization as a quick fix for achieving this vision of dynamic, efficient, easily configurable storage. The reality, however, proved to be decidedly different. In practice, virtualization alone is neither as easy as promised nor as effective. Despite the appeal of heterogeneous storage pooling, virtualization by itself is unable to deliver the expected benefits across the diverse, multi-vendor storage environment facing most organizations. It might be possible to virtualize pieces of the storage environment, but certainly not the whole thing.

Still, the goal of storage virtualization remains highly desirable. Managers desperately want to increase the utilization of storage, reallocate storage as needed, and reduce the cost of administering increasingly vast amounts of diverse storage from multiple vendors. There will be no quick fix, however, when it comes to achieving these goals--not virtualization or any other promised magic bullet. These goals certainly can be achieved, and virtualization will play a key part, but success will require organizations to pursue a holistic storage management strategy that includes virtualization as it allows IT managers to integrate, centralize, and automate the administration of diverse storage components.

Storage Virtualization

Storage virtualization itself is vaguely defined and loosely understood. To IT managers, it generally means somehow masking the complexity of different storage components so they appear as a single logical storage pool that could be administered from a central point through a simple interface.

Although the concept is attractive in its simplicity, the implementation raises vexing problems. To begin with, there is no agreement on where virtualization should occur. Some providers implemented it in the storage array, for others it resides in a box somewhere in the network, while still others put virtualization in the switch or in the host. In addition, there are almost no standard interfaces. Although highly desirable, virtualization, in practice, has turned out to be far from simple.

Each approach brings a set of advantages and disadvantages, and it is no simple task to try to combine approaches to gain the advantages of each without the disadvantages. Furthermore, what works on a small scale, falls apart when rolled out across the enterprise. For example, server-based virtualization introduces very difficult problems in regard to data locking and security when multiple servers are involved. Suddenly the organization needs some sort of distributed mechanism to manage and, although this is possible to do, it undermines the simplicity that virtualization promised.

A Management Problem

As noted above, the objectives of storage virtualization--increased storage utilization and reduced cost of operations--are correct. Virtualization alone, however, isn't going to enable organizations to achieve it. But if you use virtualization as part of a comprehensive storage management solution, it can deliver substantial value. Achieving this value requires effective management of the multiple components that make up the heterogeneous enterprise storage environment and a management layer that operates at a high level of abstraction, a level at which you can, in effect, virtualize the management of the underlying components.

A strategy to achieve increased utilization and lower operational costs requires a multi-step approach to storage management that incorporates virtualization at a number of levels. This involves storage resource management (SRM). SAN management, and storage automation. When combined with virtualization, these management pieces produce a truly holistic management strategy that enables organizations to tap into the full value of their storage investment.

SRM: The First Step

To begin with, the organization needs to identify exactly what it is storing and separate the mission-critical data from secondary data. Using an SRM tool, it can assess and classify all the stored data at the logical level.

Once the data has been classified, it becomes a straightforward task to move mission-critical data to primary storage. Secondary data can be moved to less costly storage, and the unnecessary data can be eliminated altogether. Such data classification alone allows IT managers to free up storage capacity, increase utilization, and simplify the storage environment. Virtualization makes these levels transparent to the application or user.

SAN Management: Getting Physical

Where SRM gives IT managers a logical view of the storage environment, SAN management provides a physical view from the server through the fabric and the switch to the array itself, and down to the individual spindles. These physical components are the very pieces the organization wants to virtualize in the first place.

Once the pieces are identified, the management software can map the physical storage to the logical view established by SRM. This mapping masks the virtualization by allowing storage administrators to manage the storage at the logical level while the management software masks the complexity of the underlying physical storage environment.

Although the management software knows the particulars of each physical component and how to manage it, the administrator works only through a single, consistent management interface regardless of the specific individual components. In this way, the organization can add or change physical components without disrupting the use of the logical storage. Applications and users remain unaffected by changes to the underlying physical storage environment.

Automation: Tying it All Together

What drives up the cost of ownership of storage is the amount of effort required to perform even seemingly simple tasks. It might require a dozen different steps taken in a specific order to set up the storage and protection for a Microsoft Exchange Server. There are numerous other tasks, such as vaulting a tape, recovering a file, and archiving data that the organization must do repeatedly. Each involves a series of specific steps, which must be done correctly and in order.

Virtualization combined with storage automation based on policies, defined tasks, and specified workflows eliminate the need for administrators to painstakingly perform each laborious task every time. With automation handling these common repetitive tasks and virtualization masking the underlying complexity, administrators are free to focus only on the exceptions and can thereby handle far more storage per administrator.

While the goals of virtualization are desirable, virtualization alone proved unable to achieve those goals. By incorporating virtualization into a holistic storage management strategy, however, organizations can finally take full advantage of their storage investment while reducing the cost of operating their storage infrastructure. They are able to eliminate the complexity of the storage environment while they achieve the goals of virtualization through a holistic storage management strategy consisting of SRM, SAN management, and automation.

Nigel Turner is senior vice president, BrightStor Strategy, at Computer Associates (Islandia, NY)

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