Server virtualization is a technology for partitioning one physical server into multiple virtual servers. Each of these virtual servers can run its own operating system and applications, and perform as if it is an individual server. This makes it possible, for example, to complete development using various operating systems on one physical server or to consolidate servers used by multiple business divisions.

1. The future of Server Virtualization
Server virtualization is a technology for partitioning one physical server into multiple virtual
servers. Each of these virtual servers can run its own operating system and applications, and
perform as if it is an individual server. This makes it possible, for example, to complete
development using various operating systems on one physical server or to consolidate servers
used by multiple business divisions.
Server virtualization process is the masking of server resources, including the number and
identity of individual physical servers, processors, and operating systems, from server users. The
server administrator uses a software application to divide one physical server into multiple
isolated virtual environments. The virtual environments are sometimes called virtual private
servers, but they are also known as guests, instances, containers or emulations.
There are three popular approaches to server virtualization:
 Virtual machines are based on the host/guest paradigm. Each guest runs on a virtual
imitation of the hardware layer. This approach allows the guest operating system to run
without modifications. It also allows the administrator to create guests that use different
operating systems. The guest has no knowledge of the host's operating system because it
is not aware that it's not running on real hardware. It does, however, require real
computing resources from the host -- so it uses a hypervisor to coordinate instructions to
the CPU. The hypervisor is called a virtual machine monitor (VMM). It validates all the
guest-issued CPU instructions and manages any executed code that requires addition
privileges.
 The paravirtual machine (PVM) model is also based on the host/guest paradigm -- and
it uses a virtual machine monitor too. In the paravirtual machine model, however, The
VMM actually modifies the guest operating system's code. This modification is called
porting. Porting supports the VMM so it can utilize privileged systems calls sparingly.
Like virtual machines, paravirtual machines are capable of running multiple operating
systems.
 Virtualization at the OS level works a little differently. It isn't based on the host/guest
paradigm. In the OS level model, the host runs a single OS kernel as its core and exports

2. operating system functionality to each of the guests. Guests must use the same operating
system as the host, although different distributions of the same system are allowed. This
distributed architecture eliminates system calls between layers, which reduces CPU usage
overhead. It also requires that each partition remain strictly isolated from its neighbors so
that a failure or security breach in one partition isn't able to affect any of the other
partitions.
Primary advantages of server virtualization
 Reduce number of servers: Partitioning and isolation, the characteristics of server
virtualization, enable simple and safe server consolidation. Reducing floor space, power
consumption and air conditioning costs.
 Reduce TCO: It lowers the Total Cost of Ownership (TCO) by increasing the efficiency
of server resources and operational changes, as well as virtualization-specific features. As
a result of today’s improved server CPU performance, a few servers have high resource-
usage rates but most are often underutilized.
 Improve availability and business continuity: One beneficial feature is live migration.
With live migration, virtual servers can be migrated to another physical server for tasks
such as performing maintenance on the physical servers without shutting them down.
Another great advantages are encapsulation and hardware-independence features enhance
availability and business continuity in case of a disaster.
 Increase efficiency for development and test environments: Using server virtualization to
simultaneously run various operating system environments on one physical server
enables concurrent development and test of multiple environments. In addition, because
development and test environments can be encapsulated and saved, reconfiguration is
extremely simple.
 Help move to the Cloud: ¬One major application of server virtualization is Software-
Defined Data Center (SDDC), which refers to a data center where all infrastructures --
networking, storage, CPU and security – are virtualized and delivered as a service.
Deployment, provisioning, configuration and operation of the entire infrastructure is
abstracted from hardware and implemented through software. With SDDC, the entire
data center will be controlled using a single virtualization layer. It’s one of three major
building blocks of SDDC : Network virtualization, Storage virtualization , and Server
virtualization . SDDC is one of the architectures used in Cloud Computing.
Future of Server Virtualization
Server virtualization can be viewed as part of an overall virtualization trend in enterprise IT that
includes storage virtualization, network virtualization, and workload management. This trend is
one component in the development of autonomic computing, in which the server environment
will be able to manage itself based on perceived activity. Server virtualization can be used to

3. eliminate server sprawl, to make more efficient use of server resources, to improve server
availability, to assist in disaster recovery, testing and development, and to centralize server
administration.
Server virtualization has been a real "game changer" for the datacenter and those who administer
and manage it. It has provided us with efficiency at a time when we so desperately need it.
Unfortunately, there are so few companies that are 100 percent virtualized. For those companies
that have virtualized a large amount of their servers, are they really taking advantage of all the
benefits virtualization offers?
References
http://whatis.techtarget.com/definition/autonomic-computing
http://www.techrepublic.com/blog/10-things/10-benefits-of-virtualization-in-the-data-center/#.
http://www.nec.com/en/global/solutions/servervirtualization/merit.html
http://www.howstuffworks.com/server-virtualization.htm
https://software.intel.com/en-us/articles/the-advantages-of-using-virtualization-technology-in-
the-enterprise
http://virtualizationreview.com/articles/2011/06/20/top-10-benefits-of-server-virtualization.aspx
http://www.infoworld.com/d/virtualization/top-10-benefits-server-virtualization-
177828?page=0,3
http://searchservervirtualization.techtarget.com/definition/server-virtualization
http://www.webopedia.com/TERM/S/server_virtualization.html