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A virtualized data center is a more nimble, responsive, and efficient data center. Virtualized data centers get much more productive work out of their systems, use less energy and floor space, and have higher personnel productivity. With virtualized systems, customers can respond to constantly changing IT needs much more quickly and effectively than they can with single-application discrete systems.
Virtualization has long been used in the mainframe and large system world as a safe and reliable method of improving IT efficiency. The big news is how x86 server virtualization technology is now ready for prime time. Virtualization will have the biggest impact (providing the greatest benefit to the greatest number of organizations) when applied to the truly massive numbers of x86 servers that have been multiplying amoeba-like in most organizations.
In the x86 world, there are two broad types of virtualization: O/S Virtualization and Hypervisor based virtual machines. O/S virtualization mechanisms use a single instance of an operating system (Windows or Linux) to, with the help of the virtualization software, host a large number of individual workloads. It’s kind of like how Windows on a personal computer can have Word, Outlook, Excel, and a whole bunch of other workloads open and operating at the same time.
The hypervisor approach is completely different. A hypervisor is code that sits between the guest operating systems and the hardware. The guest operating systems can be various versions of Windows and Linux, which can be mixed and matched on the same system. The hypervisor makes sure that each operating system instance gets its proper share of HW resources and also ensures that activity in one virtual machine (or partition) can’t negatively impact any other partition or the overall system.
These two methods aren’t mutually exclusive. Each has strengths and weaknesses, and each has a place in most data centers. Currently, the hypervisor approach is much more popular in the market, with VMware owning the lion’s share.
Virtualization Benefit: Utilization
The benefits from virtualization, particularly on x86 systems, are profound. The first and most dramatic improvement is in the area of system utilization. The average utilization rate for a typical x86 server is only about 6% - a shockingly low figure, and often a surprise to data center managers. This isn’t to say that there aren’t any x86 systems running at higher utilization rates; these systems definitely exist, but in almost every data center, the systems that are hitting the stops on the high side have many more barely idling boxes sitting right next to them.
The reason for this dismal situation is due to the traditional x86 usage model where a single server only hosts a single workload. Under this model, bringing a new application into the data center spawns multiple new boxes – one (or more) for production, a box for testing, a box for development, and perhaps even more boxes for training or failover needs. While the production server might see some high usage peaks from time to time, the test and development systems are often used only sporadically – lowering the average utilization rate for the entire data center.
Virtualization can quickly and easily improve average system utilization rates from the low single digits into the 50% range or higher (depending on workload and application characteristics). The benefits arising from this are impressive. The most obvious is that customers will get much more use out of their systems, and thus be able to postpone the purchase of new hardware. The fewer systems on the floor, the fewer systems that have to be maintained, managed, and secured – helping to reduce the workload on staffs that are usually stretched pretty thin.
Virtualization Benefit: Energy & Facilities
Virtualization is also one of the best ways to improve facilities issues. Currently, there is a lot of attention being focused on data center energy usage, with vendors rushing to bring out more energy-efficient offerings. Implementing virtualization pays significant dividends on both energy usage and floor space requirements. The impact on floor space is obvious – if you’re running the work of five or ten systems on a single system, you can remove the excess boxes and free up quite a bit of space.
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