What is Virtualization?
When people talk about virtualization, they’re usually
referring to server virtualization, which means partitioning one physical
server into several virtual servers, or machines. Each virtual machine can
interact independently with other devices, applications, data and users as
though it were a separate physical resource.
Different virtual machines can run different operating
systems and multiple applications while sharing the resources of a single
physical computer. And, because each virtual machine is isolated from other
virtualized machines, if one crashes, it doesn’t affect the others.
Hypervisor software is the secret sauce that makes
virtualization possible. This software, also known as a virtualization manager,
sits between the hardware and the operating system, and decouples the operating
system and applications from the hardware. The hypervisor assigns the amount of
access that the operating systems and applications have with the processor and
other hardware resources, such as memory and disk input/output.
In addition to using virtualization technology to partition
one machine into several virtual machines, you can also use virtualization
solutions to combine multiple physical resources into a single virtual resource.
A good example of this is storage virtualization, where multiple network
storage resources are pooled into what appears as a single storage device for
easier and more efficient management of these resources. Other types of
virtualization you may hear about include:
Network virtualization splits available bandwidth in a
network into independent channels that can be assigned to specific servers or
devices.
Application virtualization separates applications from the
hardware and the operating system, putting them in a container that can be
relocated without disrupting other systems.
Desktop virtualization enables a centralized server to
deliver and manage individualized desktops remotely. This gives users a full
client experience, but lets IT staff provision, manage, upgrade and patch them
virtually, instead of physically.
Virtualization was first introduced in the 1960s by IBM to
boost utilization of large, expensive mainframe systems by partitioning them
into logical, separate virtual machines that could run multiple applications
and processes at the same time. In the 1980s and 1990s, this centrally shared
mainframe model gave way to a distributed, client-server computing model, in
which many low-cost x86 servers and desktops independently run specific
applications.
While virtualization faded from the limelight for a while, it
is now one of the hottest trends in the industry again, as organizations aim to
increase the utilization, flexibility and cost-effectiveness in a distributed
computing environment. VMWare, Citrix, Microsoft, IBM, RedHat and many other
vendors offer virtualization solutions.
Why Should You Care?
Virtualization can help you shift your IT focus from
managing boxes to improving the services you provide to the organization. If
you are managing multiple servers and desktops, virtualization can help you to:
Save money. Companies often run just one application per
server because they don’t want to risk the possibility that one application
will crash and bring down another on the same machine. Estimates indicate that
most x86 servers are running at an average of only 10 to 15 percent of total
capacity. With virtualization, you can turn a single purpose server into a
multi-tasking one, and turn multiple servers into a computing pool that can
adapt more flexibly to changing workloads.
Save energy. Businesses spend a lot of money powering unused
server capacity. Virtualization reduces the number of physical servers, reducing
the energy required to power and cool them.
Save time. With fewer servers, you can spend less time on
the manual tasks required for server maintenance. On the flip side, pooling
many storage devices into a single virtual storage device, you can perform
tasks such as backup, archiving and recovery more easily and more quickly. It’s
also much faster to deploy a virtual machine than it is to deploy a new
physical server.
Reduce desktop management headaches. Managing, securing and
upgrading desktops and notebooks can be a hassle. Desktop virtualization
solutions let you manage user desktops centrally, making it easier to keep
desktops updated and secure.
