Figure 1: goals driving Virtualization initiatives (infoWorld 006)
of physical devices, improve resource utilization efficiency, reduce management costs, and simplify provisioning of computer resources is front and center in the minds of IT managers (see Figure 1). These benefits translate into tangible business impacts. Simplified provisioning improves the responsiveness of IT to business needs. Hardware consolidation and improved resource utilization reduces costs and the improved manageability makes it easier to scale the IT infrastructure as the business grows.
Enterprise, or Data Center, Virtualization is the name given to the collection of key virtualization technologies: server virtualization, storage virtualization and fabric virtualization. While these are generally deployed as separate initiatives, IT managers are increasingly considering the prospect of a fully virtualized data center infrastructure.
One of the characteristics of enterprise data centers is the existence of Storage Area Networks (SANs). There is a high
degree of affinity between SANs and server virtualization, because the connectivity offered by a SAN simplifies the deployment and migration of virtual machines. A virtual machine can be deployed on any physical server that has a connection to the SAN, rather than requiring its storage to be physically connected to its host server. Furthermore, a virtual machine can then, at least in theory, be migrated to any other physical server that is also connected to the SAN, and maintain the connection to its storage.
Of course, storage virtualization is also highly correlated with SAN infrastructures, again because the connectivity of a SAN enables many of the benefits of virtualized storage. A SAN-based storage device can be shared between multiple servers, enabling data consolidation. Conversely, a virtual storage device can be constructed from multiple physical devices in a SAN, and be made available to one or more host servers. Not surprisingly then, not only are storage devices being virtualized, but increasingly there