Once a decision to virtualize IT services has been made, successful implementation is determined by whether the virtualized system reflects an organization's needs and goals. Different organizations have different needs. For instance, an internet startup might value scalability combined with the ability to rapidly deploy new services over features like support for legacy applications and backward compatibility, which might be valued by established B2B companies with relatively few and stable user numbers. In other words, a big part of a virtualized system's success depends on implementation architecture choices. Here we'll take a look at how to choose a virtualization platform. (To learn more about why to virtualize, see The Benefits of Server Virtualization.)

Virtualized Systems Architecture

Architecturally speaking, virtualized information systems have two layers:

  • Hardware Environment
    These are the servers, storage and networking components of the data center being virtualized. It is possible to reuse the hardware already in place. In fact, virtualization supports this by providing a consistent interface to the application to be deployed even if the hardware differs. The hardware environment chosen plays a crucial role in determining the software platform to be used.
  • Software Platform
    The software layer abstracts the hardware environment to provide the hosted environments with an idealized environment. Distinct virtualization software has unique hardware requirements so when existing hardware is to be used, software choices are limited by compatibility with the hardware. Even when compatible hardware is used, the specifics influence performance. If exceptionally high performance is critical, hardware should be chosen very carefully.

Available Virtualization Platforms

VMware’s vSphere is the celebrity in virtualization’s climate-controlled data room, but it is not the only option. There are other platforms available for virtualization, including XenSource and Hyper-V, which are stable, enterprise-ready products backed by established players and that provide long-term support.

The platform to use should not be decided based on cost alone, as sub-optimal solutions will eventually necessitate additional expenditures, resulting in higher long-term costs. There is no best solution here as finding the right fit involves individual considerations. That said, there are a few pointers when it comes to choosing the best possible virtualization platform.

Choosing the Best Virtualization Platform

In terms of virtualization market trends, VMware is still the market leader, but its market share has been dropping over the last few years. According to research by Trefis released in 2014, VMware's market share dropped by 8 percent between 2008 and 2013 to 56 percent while Hyper-V gained 8 percent over the same period to capture 28 percent of the market share. This suggests that enterprises are increasingly finding Microsoft’s offering to be a credible alternative to VMware’s products. On the other hand, Citrix’s XenServer commanded only 4.3 percent of the market share despite being open source, showing that decisions are not being made solely based on the cost of these products. (To learn more about open source, see Open Source: Is It Too Good to Be True?)

When evaluating virtualizing platforms there are some must-have features and essential considerations that apply to all data centers. These provide a baseline for evaluation, and any platform worthy of consideration should include them.

Features to Look for in a Virtualization Platform

Reduction of Capital Expenditures (CAPEX)
Typically servers have low utilization levels averaging around 15 percent. Virtualization can increase throughput four-fold. This means that a company can use less hardware and reduce energy costs. Note that this must be weighed against the total cost of ownership of the virtualization platform.

System Consolidation
By running multiple applications and operating systems, an organization reduces the number of physical servers required.

Server Consolidation
This is an approach to the efficient usage of computer server resources in order to reduce the total number of servers or server locations that an organization requires.

Ease of System Management
In this context, easy management is how rapidly new services such as platform as service (PaaS), infrastructure as a service (IaaS) and software as a service (SaaS) can be deployed. It also refers to agility and speed in deploying new application stacks.

Platform Maturity
Virtualization is an expensive long-term investment which will be wasted if vendors are switched. As such, new entrants to the market may not be a good option for mission-critical data centers.

Hardware Compatibility
Virtualizing platforms have issues with hardware, including outright incompatibility and sub-optimal performance. Hosted hypervisors tend to have the greatest support for a range of hardware types, while bare-bones virtualizers are typically choosy about supported hardware. If you are planning to repurpose existing hardware, you should check if your platform of choice supports that hardware.

Total Cost of Ownership
Total cost of ownership is not just the price of purchasing a virtualization platform. Additional expenses such as guest OS licenses, training and support plus hardware should be factored in. One cost component that is often hidden is the purchase of advanced management tools. As a rule, these are not included in the initial purchase price. For instance, if you go for VMware you are likely to need vCenter Server as the installation scales up while System Center Virtual Machine Manager is the comparable offering from Microsoft to go with its Hyper-V. It might also be necessary to invest in third-party tools for auditing, capacity planning or reporting.

Technical Differences

When virtualizing, it is also important to consider technical concerns early on in the process in order to fully realize the benefits mentioned above without compromising efficiency.There are two main approaches to virtualizing:

  1. Type 1 Hypervisor
    In what's called bare-metal virtualization, a hypervisor is the first layer of software on a clean x86 system. This provides more efficiency, performance, stability and greater scalability than hosted architectures. vSphere is a good example of this approach.
  2. Type 2 Hypervisor
    In what's called hosted virtualization, virtualization is implemented on top of a standard operating system and supports the widest range of hardware. Microsoft’s Hyper-V is the best example of this approach.

The top virtualization platforms are more or less evenly matched as far as features are concerned. However, features are not the only consideration when making hypervisor choice. Some of the other important factors are hardware compatibility and cost of ownership. System support, stability and scalability deserve a long hard look as well. The key is to assess all of a platform's features and costs against your company's needs and budget. The key isn't just to virtualize. For true success, companies must find the right fit.