January 14, 2008

Server and Storage Virtualization: A Complete Solution

By Dave DuPont, CEO, SANRAD

Server virtualization is an important step toward improving overall IT efficiency. Virtual machine technology reduces the complexity and management of disparate server hardware and OS platforms. Nonetheless, server virtualization is only one component in a truly virtual enterprise infrastructure. Another critical component is storage virtualization.

Similar to server virtualization, storage virtualization creates a logical layer of storage from physical storage devices. The full benefits of server virtualization can only be realized in combination with a virtual storage layer that works in conjunction with and complements the virtual server layer. For example, dynamic virtual machine failover, a key benefit of leading server virtualization solutions, can facilitate disaster recovery. It is incomplete, however, without dynamic storage failover, a storage virtualization feature. Implementing storage virtualization, in other words, extends the benefits of an investment in server virtualization and builds upon them, providing simplified storage management, improved storage utilization and application performance, a bullet-proof disaster recovery solution, and a diminished need for proprietary vendor solutions.

Business Drivers for Storage Virtualization

The business drivers for storage virtualization are much the same as those for server virtualization. CIOs and IT managers must cope with shrinking IT budgets and growing client demands. They must simultaneously improve asset utilization, use IT resources more efficiently, ensure business continuity and become more agile. In addition, they are faced with ever-mounting constraints on power, cooling and space.

Key Benefits of Storage Virtualization

Storage virtualization provides companies with tools to address the underutilization of resources and the poor economics of silo-based storage, as well as the flexibility to respond to changing business requirements. In a storage virtualized environment, organizations achieve the full benefits of consolidation, improved resource usage and comprehensive disaster recovery. Storage virtualization also dramatically reduces power and cooling costs.

The Intelligent Network Switch: A New Approach to Storage Virtualization

Intelligent network switches with built-in storage management services, such as SANRAD’s V-Switch, have changed the virtual storage paradigm from a model of expensive proprietary vendor lock-in to one of low-cost open support for total storage flexibility. Open storage virtualization enables IT managers to improve overall storage utilization by allowing capacity from any storage array to be combined in centrally managed, virtual storage pools. IT managers can dynamically reduce capacity for applications that are not growing and reuse that capacity for those which are. This can eliminate the need to procure new storage or, at a minimum, delay acquisition.

Intelligent network switches also enable organizations to easily link storage hardware and software solutions from multiple storage vendors, removing the burden of proprietary vendor lock-in and simplifying tasks such as data replication, mirroring and data migration. For example, when a storage network is comprised of disparate systems, even from the same vendor, data migration is time-consuming and application-disruptive. In a typical scenario, the application is taken offline, data is moved to tape and then restored. Intelligent integrated network switches permit data to be migrated in real time, from any storage array to any other storage array, without taking applications offline. Storage virtualization utilizing intelligent switches provides non-disruptive online migration that eliminates downtime and greatly reduces administrators’ involvement in data or server migration.

Other benefits include a common set of management, provisioning and replication tools that lower the total cost of ownership (TCO) by reducing the number of tools and people necessary to manage storage and eliminating the requirement to purchase multiple licenses for every storage device.

The Value of Incorporating Storage Virtualization with Server Virtualization

Storage virtualization complements server virtualization by providing easy, centralized management, flexible provisioning, and improved disaster recovery. With disaster recovery, storage virtualization enables one storage system to fail over to another storage system with minimum disruption. However, with most storage virtualization solutions the failover is not instantaneous and manual intervention is required. Therefore, the benefit of overall instantaneous system recovery is lost. A network-based intelligent switch architecture, as depicted in the illustration below, addresses this discrepancy between the server and storage, providing instantaneous failover.

Intelligent Switch ArchitectureIn the event of a complete disaster at one location, the virtual server there fails over to the server at the remote location without any interruption. If the primary storage system is affected by the same disaster, the other dynamically responds to the virtual server. This ensures zero hours RTO (recovery time objective) and zero hours RPO (recovery point objective).

The new generation of open virtualization solutions delivered via an intelligent switch with storage management services provides enterprise-class disaster recovery without the expenses imposed by proprietary storage architectures. Other benefits of storage virtualization include the ability to store multiple copies of virtual machine images for high availability and the ability to simplify physical storage infrastructure upgrades. Storage virtualization and server virtualization work together to solve the complex equation of a truly virtual infrastructure.


Server virtualization is changing the face of the server world with simple and effective tools to deploy and manage virtual servers. The same is now true for storage virtualization, using intelligent network switches that allow IT managers to realize more complete value from their virtual infrastructures. By enabling more efficient use of resources, eliminating vendor hardware and software dependencies, delivering seamless disaster recovery, and offering an attractive TCO, intelligent network switches with integrated storage services provide the best approach to storage virtualization. Combined with server virtualization, this new evolution allows customers to deploy a comprehensive virtual IT infrastructure, with virtual servers and virtual storage used to overcome the limitations of their physical counterparts.

About Dave DuPont

Dave DuPont is the chief executive officer of SANRAD, a leading supplier of storage area network (SAN) connectivity and management solutions. DuPont has almost two decades of experience in the IT industry and he holds a B.S. in mechanical engineering from Cornell University and an MBA from Harvard.

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