Reflections on virtualization for the SMB.

In both the server and storage industries, the potential for business in serving small to medium businesses can be substantial. For many vendors, it is uncharted territory and an appreciation of the pain points of the SMB is a key action item.

It is all too tempting to look at the SMB as just a smaller version of the enterprise data center. But the yawning difference between the SMB and the enterprise in terms of the delta in budgetary resources, staffing resources, legacy resources and the IT mission makes this vision difficult to sustain.

Where commonality does exist is in the requirement for the efficient and cost-effective use of servers and storage. Both the SMB and the enterprise are increasingly committed to cost reduction and consolidation in server and storage acquisition and operation. Consolidation in particular is popular, since it represents the use of less space, less electricity, and fewer hours and personnel committed to management of the assets.

To attain these lofty goals, the SMB can now look to virtualization as a strategy. Properly applied, virtualization reduces total cost of operation and boosts performance of the assets that have been virtualized.

Server Virtualization 

For purposes of this discussion, virtualization comes in two flavors: server and storage. Server virtualization creates a level of abstraction permitting a single computer to act as several computers. It gives the user the impression that multiple servers exist on a single box. Each server session enjoys its own dedicated memory space, dedicated storage space and emulated processor.

There are two major applications offering server virtualization support. One is Microsoft Virtual Server 2005 R2 (For the desktop, Microsoft offers Virtual PC, which came to the Redmond giant with the acquisition of Connectix. This was the same implementation that allowed Mac systems to run DOS type sessions to achieve cross platform compatibility.) The other is VMware, the godfather of server virtualization applications running a broad series of operating systems.

Other major virtualization applications are available from companies such as SWsoft and XenSource, although they represent a small piece of the virtualization pie. There also are tools that can be used for deploying virtual servers, migrating servers and protecting servers aside from those offered by the virtualization vendors themselves, such as Acronis True Image and Acronis Full Circle. In addition to migrating from the physical to virtual environments, these tools also can be used to migrate from a virtual server to a dissimilar hardware-based virtual server or from a virtual server back to a physical server. Working together, the Acronis tools also can be used for backup and disaster recovery of virtual servers in an SMB and enterprise environment.

Most recently, VMware has taken aggressive steps to bring server virtualization to the SMB, focusing on that key SMB requirement: Ease of use. VMware Server, VMware's low-end virtual generator, has been free since July 2006. Some 70% of its 1.2 million downloads is reported to have gone to small or medium-sized businesses. To satisfy that essential ease of use requirement, VMware is offering VirtualCenter for VMware Server.

VirtualCenter is a single management console for configuring, provisioning, and managing virtual machines. It includes a high-availability module and a VMotion virtual machine module that migrates from one physical server box to another. It also includes a dynamic resource allocation module for assigning memory, CPU duty cycles, and network bandwidth between virtual machines on a pool of physical servers. The SMB version of VirtualCenter is restricted to the VMware Server, an older form of virtual server technology that translates virtual machine needs through the physical server's operating system.

Storage Virtualization 

Storage virtualization is well defined in Tom Clark's definitive work Storage Virtualization: "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." Even a basic understanding of virtualization delivers both data center manager and SMB multiple benefits: a better handle on downtime, better general storage performance, fewer problems of lost data, and the ability to aggregate storage devices, delivering best use of storage assets.

The need for storage virtualization appears, as a rule, when it is necessary for the SMB to implement a storage area network (SAN). This determination is often a function of the amount of data to be stored. If storage requirements require more than 2 TB, a SAN is widely considered by IT professionals to be the preferred solution to direct- or network-attached storage. This is because SANs allow storage scaling over time and provides such benefits as high availability, high performance, scalability and ease of management.

Virtualization in a SAN involves abstracting the logical (or virtual) presentation of stored data from the physical disk asset where the data actually rests. The result is a more efficient use of storage assets. Data could migrate from one device to another in the background while the virtual presentation of the storage remains constant

Storage virtualization is anything but new, even if the phrase is new to the SMB. The reorganization of storage in a RAID array with data striping onto multiple drives is a type of virtualization. Virtual tape was pioneered by IBM many years ago. In fact, the most basic type of virtualization is disk partitioning, where multiple partitions appear as separate disks to the operating system.

Why Virtualize?

The SMB can look at virtualization as a route to achieve a variety of benefits in terms of storage management, many of which have been discussed here. But taking a long view, virtualization is a reliable route to the development of a utility infrastructure, where server processing and storage are managed as resources similar to the way electricity and water are managed for homes and businesses.

Utility IT infrastructure is highly responsive and makes the best use of available hardware investments. Take, for example, the need to provide IT support for a new business process. In a conventional storage networking environment, satisfying this need will likely require the purchase of servers and either internal disks or an attached array to house the applications and data that this new process will require.

In a utility infrastructure, the new application is provisioned with processing power, and storage space is allocated from a pool of resources within the structure. The application is housed in a virtual machine and the data in support of the new business process is stored on a virtual storage volume. In cases like this one, any new capital expenditure for servers and disk storage will be commodity purchases made to increase the size of the processing and storage pool, not specifically to support the new business process.

Virtualization is an enabling technology for a utility infrastructure. Virtualization is the means by which the processing and storage are abstracted and managed separately from the underlying hardware layer.

From the point of view of server and storage management, resource allocation and IT support for SMB applications, virtualization makes a great deal of sense. Once the SMB gets over the intimidation of the V-word, the only challenge will be to choose whose utility infrastructure will best solve prevailing IT/business problems.

Mark Ferelli, formerly the chief editor of Computer Technology Review, is a freelance writer and storage specialist based in North Hollywood, CA. He can be reached at [e-mail].