Myths persist about advantages and disadvantages of virtualization

Server virtualization is now pervasive, but it's not uncommon to still hear myths about the advantages and disadvantages of virtualization.

As with any new technologies or trends, server virtualization faced a hefty dose of skepticism when VMware first began pushing its products. Many questioned whether virtualization should even have had a place in enterprise data centers.

Today, the vast majority of large companies rely on virtualization, but that doesn't mean it's gained universal traction. Unfortunately, some of the myths that virtualization faced when it first grabbed our attention persist today. This month, we're asking our Advisory Board members what myths they still hear about the advantages and disadvantages of virtualization and how they debunk those myths.

Jason Helmick, Concentrated Technology LLC

Myths and mysteries have plagued virtualization platforms for years. Fortunately, the tools to debunk those myths are already in your hands.

Think of the blanket statements you have heard used to convince decision makers that virtualization is either good or bad. Statements such as:

  • Virtualization is more/less secure than physical servers.
  • Virtualization performs better/worse than physical servers.
  • Virtualization is easier/harder to monitor and manage.

These statements about the advantages and disadvantages of virtualization can be debunked with the realization that they are all true. Yes, all true. After virtualizing a line-of-business application, an IT pro may gain better performance due to better resource management. However, the same application may perform worse if the IT pro manages resources poorly.

With all of the myths about the advantages and disadvantages of virtualization over the years, it comes down to the knowledge and experience of the IT pro. If you're good at virtualization, you understand your platform and you can plan, monitor and adjust accordingly, then all the positive myths will come true. I'm sure you have seen what happens when an admin lacking knowledge and experience virtualizes servers and applications.

The answer is to make sure you're the IT pro equipped with the right knowledge, making the best myths come true.

Brian Kirsch, Milwaukee Area Technical College

Over the years I've heard many myths about the advantages and disadvantages of virtualization.

Virtual machines are slower than hardware
This myth does have some truth to it. If your server is running at 100% capacity for both CPU and memory, then, yes, the added overhead of a hypervisor will create an environment where a physical server will outperform a virtual server. However, most servers don't run at 100%, so this argument is rarely valid. And in the rare cases where a server does run at 100%, it might not be a good fit for virtualization.

Virtual machines are not as stable as real hardware
With dedicated hardware you have full hardware support from the vendor to ensure proper temperature, drivers and high availability. While this is true to a degree, it  also means more overhead that Windows needs to manage. Monitoring dozens of sensors and loading custom drivers for unique hardware are all things that Windows can do but wasn't designed for. Windows was designed to run applications, and loading the minimal set of drives (VMware Tools) and no hardware sensors or footprint allows Windows to be Windows and just run applications.

My application is too intense for virtualization
This is one of the biggest hurtles in the virtualization path. Oftentimes this argument is used because the application vendor or owner is convinced that the criticality of the application should correspond to how much resources it needs to run properly. A spam-filtering server might be critical to an environment to prevent unwanted email, but that does not mean it requires dedicated hardware. The best way to combat this myth is to use monitoring tools such as Solar Winds Server Application Monitor or Dell Foglight to show application owners the real statistics about the server.

Virtualization is still scary and full of many myths for many people. The method of throwing hardware at problems without always examining it first is alive and well today. It's not because of a lack of effort in wanting to examine the correct solution, but it's often because of the fast-paced deadline-driven nature of IT.

Rob McShinsky, Dartmouth-Hitchcock Medical Center

The biggest myths I hear today are related to hypervisor support. Vendor support (or lack of support) for a particular hypervisor have been the greatest purveyors of this myth. Many [products] support any hardware vendor and maybe VMware, but Hyper-V or XenServer are often deemed unsupported. Operating system support, driver support or kernel level support all make sense, but a properly architected virtualization environment will have better performance, resiliency and disaster recovery than most hardware-only approaches. Having many years of experience with Hyper-V, it is often comical to listen to vendors trying to explain why their application will not work on Hyper-V. I've heard everything from, "the virtual disks are too slow," to "the network is inefficient."

Recently, I had a vendor say it could not support a particular hypervisor because the management interface is "clunky." The vendor conceded that hypervisor performance metrics were on par with VMware, but because it did not like the management software, it would not support Hyper-V as a target platform. If application performance is acceptable, why should the vendor care about how I manage my virtual machines?

The key to busting these myths is to define your organization's goals as they pertain to your infrastructure needs and getting your management on board to meet those needs.

Application vendors, please stop the myths about hypervisor weaknesses based on your bias, lack of knowledge or laziness. Take a little time, test your product and give your customers real data about resource expectations and leave the hypervisor out of it.

Dave Sobel, Level Platforms Inc.

Many of the original virtualization myths have cleared up now that the technology is well established. In fact, the old myths about performance being poor and line of business applications being unsupported seem to have passed. Today, one of the big remaining myths is that virtualization is the cloud. Virtualization enables the cloud, of course, but the two are distinct technologies.

The other big myth that remains about virtualization is that it's a new technology. Virtualization dates back to some of the earliest computers, so this couldn't possibly be true, and thus a simple history lesson helps debunk this myth. Finally, the last myth is that virtualization is risky. Showing a customer virtualization's track record with large corporations quickly proves this myth untrue.

This was first published in January 2014

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