Virtualization has been a major data center trend for a number of years, being driven by companies’ desire for greater operating efficiency, lower capital costs, better use of existing floor and rack space, and reduced energy consumption. The heart of virtualization is the hypervisor or virtualization layer, which hides the server hardware and presents a “generalized” environment in which processes can run. These processes, or virtual machines, can be anything from single applications to entire operating systems.
A number of benefits accrue from virtualization; one of the key features underlying these benefits is that the hypervisor presents a common platform to virtual machines regardless of the underlying hardware. Thus, the virtual machines need not be tailored to a variety of different servers, storage systems and so on—instead, they need only operate using the common virtualized environment. This characteristic enables, for instance, easy portability of virtual machines among different hardware systems (as long as those systems run the same hypervisor). Furthermore, backup (or, more particularly, restoration) is simplified because of the single, unifying virtualization layer.
In addition, this approach allows multiple virtual machines to run on a single server while maintaining isolation. Instead of dedicating an entire server to a single process—a configuration that, according to some estimates, yields hardware utilization rates below just 10% in some data centers—servers can ran as many processes as necessary to increase utilization while still dedicating sufficient resources to each process.
Naturally, over time virtual machine technology has expanded and improved, encompassing more features and capabilities in critical areas such as, for security, security and operating isolation. Here’s a snapshot of the current state of virtual machines, as well as where they may be headed in coming years.