Virtualization: Myths vs. Facts
Examine fifteen common myths surrounding virtualization, including many that prevent IT administrators (or their bosses) from getting the maximum value from virtualization. This paper is designed to be vendor-neutral; in other words, the basic concepts and advantages are the same whether you choose to use Citrix XenServer, VMware vSphere, Microsoft Hyper-V, or one of the many Linux-based solutions. We'll break the reasons into three broad categories (Cost/ROI, Performance, and Other), allowing you to focus in on a specific area if desired, or you can review the entire white paper for a broader view.
In this section, we'll focus on seven different myths commonly heard relative to either the cost of getting into virtualization or the costs once there. We'll discuss each and why each should not be a major consideration in deciding on a virtualization strategy.
Myth 1: Virtualization is too expensive
Many people look at the cost of virtualization software, training, and the cost of shared storage and think that virtualization is too expensive. While all these things cost money, there are ways to save on each, and the simple fact that you will require far fewer servers (saving Capital Expenditure (CapEx) - budgetary dollars) will save a lot - usually more than the extra costs just listed. Add to that the savings in Operational Expenditures (OpEx), the day-to-day costs of heating, cooling, managing, etc., and the savings can really add up. Each major vendor in virtualization has a free product offering to get you started, and there are several options for creating shared storage out of local disks, such as VMware's vSphere Storage Appliance (VSA). As for the costs of training, there are computer based training (CBT) options, books, blogs, etc., that can fill in the gap if instructor-led training isn't an option. They can also be used to supplement the things covered in a real or virtual classroom. For all but the smallest of companies, virtualization saves money.
Myth 2: It is only for large companies
Another common misconception is that virtualization is only for large companies with extensive staff, shared storage, thousands of servers, etc. In fact, virtualization can be helpful to companies of almost all sizes. Unless you only have one server, virtualization can decrease the number of servers needed in the organization, along with the decrease in OpEx associated with fewer servers in use. Couple these savings with some of the other methods of reducing costs listed in the previous myth and it is hard for many businesses not to virtualize.
Myth 3: The reported consolidation ratios are too high (vendors are inflating what we can expect to actually get)
When consolidation ratios (the number of physical servers that can be consolidated on a single server running a virtualization platform) are discussed, many assume that the numbers reported by vendors of 20:1 or even 15:1 are overly optimistic. They may or may not be, depending on the workloads that need to be virtualized. In fact, in some cases they are lower than what you will see in your environment. The numbers reported are similar to the stickers on new cars advertising a certain gas mileage or on a new appliance estimating the annual cost of operating the appliance. In all these cases, they are averages, or values calculated based on a specific test under specified conditions. The key idea here is that even if the consolidation ratio were just 2:1, that would still cut the number of servers in use in half (and remember the associated operating costs will be cut roughly in half as well). In fact, for extremely large workloads, there may even be a 1:1 ratio, but even then, the advantages of virtualization (such as being able to restart the application quickly after a hardware failure, having fewer passive standby servers laying around in case a failure occurs, being able to restart the VM at a remote location in case the primary site fails, etc.) may still make the effort worth the cost. The issue of large workloads and virtualization will be discussed further in the performance section.
Myth 4: Consolidation ratios are the most important factor in determining success
The idea that the consolidation ratio expected is a driver for determining if a particular virtualization project makes sense or not is just silly. Obviously, larger ratios will save more money, but even small ratios will lead to savings, and why pass up any savings in today's economic environment?
Myth 5: Virtualization leads to server sprawl
This is one of the few myths that actually has some merit. Virtualization can lead to sprawl if not properly managed. It is easy to create additional VMs, and that can quickly get out of control without some Information Lifecycle Management (ILM) policies. To help combat this problem, there are tools from many third parties that look for these VMs and provide reports on utilization, last time they were powered on, etc.