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Why is server virtualization important?

 

To appreciate the role of virtualization in the modern enterprise, consider a bit of IT history.

 

Virtualization isn't a new idea. The technology first appeared in the 1960s during the early era of computer mainframes as a means of supporting mainframe time-sharing, which divides the mainframe's considerable hardware resources to run multiple workloads simultaneously. Virtualization was an ideal and essential fit for mainframes because the substantial cost and complexity of mainframes limited them to just one deployed system -- organizations had to get the most utilization from the investment.

 

The advent of x86 computing architectures brought readily available, relatively simple, low-cost computing devices into the 1980s. Organizations moved away from mainframes and embraced individual computer systems to host or serve each enterprise application to growing numbers of user or client endpoint computers. Because individual x86-type computers were relatively simple and limited in processing, memory and storage capacity, the x86 computer and its operating systems (OSes) were typically only capable of supporting a single application. One big shared computer was replaced by many little cheap computers. Virtualization was no longer necessary, and its use faded into history along with mainframes.

 

But two factors emerged that drove the return of virtualization technology to the modern enterprise. First, computer hardware evolved quickly and dramatically. By the early 2000s, typical enterprise-class servers routinely provided multiple processors and far more memory and storage than most enterprise applications could realistically use. This resulted in wasted resources -- and wasted capital investment -- as excess computing capacity on each server went unused. It was common to find an enterprise server utilizing only 15% to 25% of its available resources.

 

The second factor was a hard limit on facilities. Organizations simply procured and deployed additional servers as more workloads were added to the enterprise application repertoire. Over time, the sheer number of servers in operation could threaten to overwhelm a data center's physical space, cooling capacity and power availability. The early 2000s experienced major concerns with energy availability, distribution and costs. The trend of spiraling server counts and wasted resources was unsustainable.


Server virtualization reemerged in the late 1990s with several basic products and services, but it wasn't until the release of VMware's ESX 1.0 Server product in 2001 that organizations finally had access to a production-ready virtualization platform. The years that followed introduced additional virtualization products from the Xen Project, Microsoft's Hyper-V with Windows Server 2008 and others. Virtualization had matured in stability and performance, and the introduction of Docker in 2013 ushered in the era of virtualized containers offering greater speed and scalability for microservices application architectures compared to traditional VMs.

 

Today's virtualization products embrace the same functional ideas as their early mainframe counterpart. Virtualization abstracts software from the underlying hardware, enabling virtualization to provision and manage virtualized resources as isolated logical instances -- effectively turning one physical server into multiple logical servers, each capable of operating independently to support multiple applications running on the same physical computer at the same time.

 

The importance of server virtualization has been profound because it addresses the two problems that plagued enterprise computing into the 21st century. Virtualization lowers the physical server count, enabling an organization to reduce the number of physical servers in the data center -- or run vastly more workloads without adding servers. It's a technique called server consolidation. The lower server count also conserves data center space, power and cooling; this can often forestall or even eliminate the need to build new data center facilities. In addition, virtualization platforms routinely provide powerful capabilities such as centralized VM management, VM migration (enabling a VM to easily move from one system to another) and workload/data protection (through backups and snapshots).