Databases Reference
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example, some of the ways virtualization software presented storage to a virtual server meant it was
inherently slow, and some virtualization software architecture meant it could only assign
relatively low amounts of memory to a virtual server. Because of these issues, it was quite a few
years before organizations I worked in considered mixing SQL Server with virtualization.
However, these technical limitations quickly disappeared, so the pace of adoption increased,
justii ed by benei ts that business and technical teams couldn't ignore any longer. The following sec-
tions describe the main benei ts of using virtual servers:
Business Benefi ts
Selling the idea of virtualization to a business is easy; in fact, it's too easy. Even worse, I've had
i nance directors tell me that I can design
only
virtualized infrastructures for them regardless of
what the IT teams want — or, more worryingly, need! From a business perspective, the major driver
for using virtualization is obviously cost reduction. While the cost of physical servers has dropped
over time, the number we need has increased, and increased quite quickly too. Today, even a
relatively small business requires several servers to deploy products such as Microsoft's SharePoint
Server or Exchange Server, with each server performing perhaps a compartmentalized role or
high-availability function. Therefore, even though server hardware became more powerful, their
“average utilization” dropped — and often to very low values. For example, I'm willing to bet that
if you checked one of your domain controllers, its average CPU utilization would constantly be
under 30%. That means there's 70% of its CPU utilization that could be used for something else.
Therefore, it was no surprise when even systems administrators, IT managers, and CIOs started
to question why they had 10 servers running at 10% utilization and not 1 running at 100%. The
potential cost savings, often described by businesses as
the savings from consolidation,
can be
realized with virtualization by migrating from multiple underutilized servers to a single well-utilized
server. In addition to cost savings, other benei ts of consolidation can have a big impact on a
business too. For example, at one company where I worked, we virtualized a lot of older servers
because the facilities department couldn't get any more power or cooling into a data center.
In reality, the savings aren't as straightforward as the 10 times 10% utilization example, but it
does demonstrate why both business teams and technical teams began taking a big interest in
virtualization.
Technical Benefi ts
For IT teams, adopting virtualization has also meant needing to learn new skills and technologies
while changing the way they've always worked to some degree. However, despite these costs, IT
teams across the world have embraced and deployed virtualization solutions even though it likely
represented the biggest change in their way of working for a generation. This section looks at the
benei ts that drove this adoption.
One of the main benei ts comes from consolidation. Before virtualization was available, data centers
had stacks of servers hosting lightweight roles, such as domain controllers, i le servers, and small
database servers. Each of these functions had to either share a physical server and operating system
with another function or have its own dedicated physical server deployed in a rack. Now, using
virtualization we can potentially deploy dozens of these low-utilization functions on a single
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