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
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.
WHAT TO CONSIDER
Since virtualization makes it easy to set up new virtual servers, you
may end up with a lot of servers to manage. Each server needs to be
managed just as if it was a physical server. Keeping track of where
everything — and how your virtual resources are using physical
resources — is vital, so shop for solutions that have easy-to-use tools
that help you monitor and measure use.
Virtualization isn’t a magic bullet for everything. While many
solutions are great candidates for running virtually, applications that
need a lot of memory, processing power or input/output may be best left
on a dedicated server.
For all of the upside virtualization isn’t magic, and it can
introduce some new challenges. But in most cases the many cost and
efficiency advantages will outweigh any issues, and virtualization will
continue to grow gain popularity.
Did this help you understand virtualization? Let me know, and send
me any additional questions you have on the topic. Also, please send
your suggestions for other technology terms and areas that you’d like
explained in upcoming columns. You can reach me at amitsharma6388@gmail.com or my Twitter handle, lauriemccabe. For perspectives on other industry topics, visit my blog at networkharp.blogspot.com
