Several years ago, server virtualization rolled into the data center with all of the outrageous promises and unbelievable claims of a sideshow barker. Experts and vendors claimed it was going to improve server efficiency, shrink your infrastructure, slash bloated power bills, make cumbersome administrative tasks disappear and cure the common cold. The sales pitch was smooth and we all bought in, but has virtualization fulfilled the promises? Let's take a look at one of those lofty claims and see if it held up to real world experiences.
Did your infrastructure shrink when you implemented virtualization? That really depends on a number of factors. I saw many organizations that had an extremely poor first-phase implementation. In many cases, they did not see any real reduction in infrastructure, at least not on the level promised. This was not due to shortcomings in virtualization technology. Instead, this was more the fault of "overselling" without providing the necessary qualifiers.
Virtualizing multiple workloads onto a single physical server required more memory than the average server was shipping with. In this initial wave of virtualization, most organizations installed hypervisors on repurposed hardware that was not configured for virtual workloads. Due to these resource limitations, the initial wave of virtualization did more to absorb future growth than it did to shrink the data center. However, the subsequent generations of hardware were designed with virtualization in mind, and it enabled much higher memory densities. As organizations began to deploy virtual environments on the purpose-built hardware, there was a boom in virtualization. However, data centers still were not shrinking. This time, though, it was not because virtualization was failing to meet server efficiency goals.
Businesses realized that the cost of implementing new technology had just gone down, and they leveraged that to implement additional technologies. Servers cost less to deploy and could be provisioned in minutes instead of weeks, so the floodgates opened. This phenomenon became known as virtual sprawl, and it consumed resources at an unbelievable rate. It wasn't that virtualization was not delivering on server efficiency promises, it was more an issue of achieving consolidation ratios high enough to outpace this new boom in demand.
With the spotlight now shining on virtualization, both hardware vendors and hypervisor development teams have increased their efforts to make better use of virtual resources. While the number of virtual machines took off, advancements in virtualization and server platforms allowed the overall data center footprint to not only remain steady, but to actually shrink. At this point, virtualization was truly doing more with less.
So, was virtualization the savior of the modern server? In many ways, the answer is yes. In fact, it may have also been the savior of many businesses. It lowered the technology barrier of entry at a time when financial markets were uncertain and few businesses had budgets to expand their technology investments. Instead of simply holding the line, virtualization allowed these businesses to actually expand and implement new technologies.
At the same time, virtualization brought along some unintended consequences. The very factors that made virtual servers easier to deploy also made them more difficult to administer. This was an organizational challenge, but one that echoed in almost every IT shop as they experienced the growing pains of implementing a virtual infrastructure. Server administration teams initially deployed most virtual environments. While they were virtualizing physical storage and networking assets within their new environments, the storage and networking teams were either not invited to the party or chose not to participate. Soon, there were network issues that the networking teams could not see or touch, and storage issues that left the storage administration teams trying to identify bottlenecks inside of a black box where they had no visibility. Most organizations realized this problem as their technology teams were sitting around a table pointing fingers at each other after a major outage. While virtualization technology allowed the organization to reach higher levels of server efficiency, legacy organizational practices threatened to negate all these benefits.
Did virtualization fail us? Not at all. I think virtualization has lived up to all of its initial promises, though I would have to say the timeline did stretch quite a bit. For the most part, it was the limitations of physical resources that initially held virtualization back. Later, it was the reluctance of organizations to adapt to new paradigms that threatened to undermine the dramatic gains of virtualization. In the end, though, I cannot imagine a modern technology landscape without virtualization. It was not a magic pill, immediately easing our technology pains. Instead, it was a treatment plan, putting in place a series of steps to not only address our ailments, but to leave us stronger than when we began.