Dz25764770

Mr. Milind Ramesh Kolte / International Journal of Engineering Research and Applications
(IJERA)ISSN: 2248-9622www.ijera.com
Vol. 2, Issue5, September- October 2012, pp.764-770
Survey Paper On Different Virtualization TechnologyWith Its
Merits And Demerits On Organization
Mr. Milind Ramesh Kolte
M.Sc. Computer Application (Semester –III)
Shree Ramkrishna Instituteof Computer Education
& Applied Sciences, Surat-395009.Gujarat, India.

Abstract
A Virtualized System includes a new layer The application is installed and runs directly on the
of software, the virtual machine monitor. The OS, which in turn runs directly on the computer’s
VMM's principal role is to arbitrate accesses to hardware. The application’s user interface is
the underlying physical host platform's resources presented via a display that’s directly attached to this
so that multiple operating systems (which are machine. This simple scenario is familiar to anybody
guests of the Virtual Machine Monitor) can share who’s ever used Windows.
them. The VMM presents to each guest OS a set of
virtual platform interfaces that constitute a virtual
machine (VM). Once confined to specialized,
proprietary, high-end server and mainframe
systems, virtualization is now becoming more
broadly available and is supported in off-the-shelf
systems based on Intel architecture (IA)
hardware. Virtualization technology provides
hardware support for processor virtualization, Operating
enabling simplifications of virtual machine
monitor software. Resulting VMMs can support a
System
Hardware
wider range of legacy and future operating
systems while maintaining high performance.

Keywords – Virtualization, VMM, Intel Physical Machine Application
Architecture, legacy OS
Figure – 1: A System without virtualization
I. INTRODUCTION
Virtualization is one of the hottest trends in But it’s not the only choice. In fact, it’s often
information technology today. This is no accident. not the best choice. Rather than locking these various
While a variety of technologies fall under the parts together—the operating system to the hardware,
virtualization umbrella, all of them are changing the the application to the operating system, and the user
IT world in significant ways. interface to the local machine—it’s possible to loosen
Virtualization is software technology which the direct reliance these parts have on each other.
uses a physical resource such as a server and divides it Doing this means virtualizing aspects of this
up into virtual resources called virtual machines environment, something that can be done in various
(VM's). Virtualization allows users to consolidate ways. The operating system can be decoupled from
physical resources, simplify deployment and the physical hardware it runs on using hardware
administration, and reduce power and cooling virtualization, for example, while application
requirements. While virtualization technology is most virtualization allows an analogous decoupling
popular in the server world, virtualization technology between the operating system and the applications
is also being used in data storage such as Storage Area that use it. Similarly, presentation virtualization
Networks, and inside of operating systems such as allows separating an application’s user interface from
Hyper-V (Hypervisor). the physical machine the application runs on. All of
these approaches to virtualization help make the links
II. UNDERSTANDING VERTUALIZATION between components less rigid. This lets hardware
To understand modern virtualization and software be used in more diverse ways, and it
technologies, think first about a system without them. also makes both easier to change. Given that most IT
Imagine, for example, an application such as professionals spend most of their time working with
Microsoft Word running on a standalone desktop what’s already installed rather than rolling out new
computer. deployments, making their world more malleable is a
good thing.

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Each type of virtualization also brings other benefits Hardware virtualization can be accomplished in
specific to the problem it addresses. Understanding various ways, and so Microsoft offers several different
what these are requires knowing more about the technologies that address this area.
technologies themselves. Accordingly, the next They include the following:
sections take a closer look at each one. 1.) Hyper-V (Windows Server 2008)
2.) Virtual Desktop Infrastructure (VDI)
III. VIRTUALIZATION TECHNOLOGIES 3.) Virtual PC 2007
A. Hardware Virtualization 4.) MS Enterprise Desktop Virtualization
For most IT people today, the word (MED-V)
―virtualization‖ conjures up thoughts of running
multiple operating systems on a single physical B. Presentation Virtualization
machine. This is hardware virtualization, and while Much of the software people use most is
it’s not the only important kind of virtualization, it is designed to both run and present its user interface on
unquestionably the most visible today. the same machine. The applications in Microsoft
The core idea of hardware virtualization is Office are one common example, but there are plenty
simple: Use software to create a virtual machine (VM) of others. While accepting this default is fine much of
that emulates a physical computer. By providing the time, it’s not without some downside. For
multiple VMs at once, this approach allows running example, organizations that manage many desktop
several operating systems simultaneously on a single machines must make sure that any sensitive data on
physical machine. those desktops is kept secure. They’re also obliged to
spend significant amounts of time and money
managing the applications resident on those
machines. Letting an application execute on a remote
server, yet display its user interface locally
Operating Operating Presentation virtualization can help.
System 1 System 2 ..
Hardware Virtualization
.
Hardware
Presentation
Applicatio Virtualization
Physical Machine
n

Virtual Machine
Operating System
Figure – 2: Hardware virtualization
Hardware
When used on client machines, this approach
is often called desktop virtualization, while using it on Figure – 3: Presentationvirtualization
server systems is known as server virtualization. This approach allows creating virtual
Desktop virtualization can be useful in a variety of sessions, each interacting with a remote desktop
situations. One of the most common is to deal with system. The applications executing in those sessions
incompatibility between applications and desktop rely on presentation virtualization to project their user
operating systems. For example, suppose a user interfaces remotely. Each session might run only a
running Windows Vista needs to use an application single application, or it might present its user with a
that runs only on Windows XP with Service Pack 2. complete desktop offering multiple applications. In
By creating a VM that runs this older operating either case, several virtual sessions can use the same
system, then installing the application in that VM, this installed copy of an application.
problem can be solved. Running applications on a shared server like
Server virtualization also makes restoring this offers several benefits, including the following:
failed systems easier. VMs are stored as files, and so 1.) Data can be centralized.
restoring a failed system can be as simple as copying 2.) The cost of managing applications can
its file onto a new machine. Since VMs can have be significantly reduced.
different hardware configurations from the physical 3.) Organizations need no longer worry
machine on which they’re running, this approach also about incompatibilities between an
allows restoring a failed system onto any available application and a desktop operating
machine. There’s no requirement to use a physically system.
identical system. 4.) Presentation virtualization can improve
performance.

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Microsoft’s presentation virtualization technology is
Windows Terminal Services. First released for Application Logic
Windows NT 4, it’s now a standard part of Windows
Application Virtualization
Server 2008. Terminal Services lets an ordinary
Windows desktop application run on a shared server
machine yet present its user interface on a remote
system, such as a desktop computer or thin client.
While remote interfaces haven’t always been viewed
through the lens of virtualization, this perspective can Operating System
provide a useful way to think about this widely used
technology. Hardware
C. Application Virtualization
Virtualization provides an abstracted view of Figure – 4: Applicationvirtualization
some computing resource. Rather than run directly on Application virtualization makes deployment
a physical computer, for example, hardware significantly easier. Since applications no longer
virtualization lets an operating system run on a compete for DLL versions or other shared aspects of
software abstraction of a machine. Similarly, their environment, there’s no need to test new
presentation virtualization lets an application’s user applications for conflicts with existing applications
interface be abstracted to a remote device. In both before they’re rolled out. And as Figure 4 suggests,
cases, virtualization loosens an otherwise tight bond these virtual applications can run alongside ordinary
between components. applications—not everything needs to be virtualized.
Another bond that can benefit from more
abstraction is the connection between an application D. Other VirtualizationTechnology
and the operating system it runs on. Every application This overview looks at three kinds of
depends on its operating system for a range of virtualization: hardware, presentation, and application.
services, including memory allocation, device drivers, Similar kinds of abstraction are also used in other
and much more. Incompatibilities between an contexts, however. Among the most important are,
application and its operating system can be addressed 1.) Memory Virtualization
by either hardware virtualization or presentation  The term memory virtualization decouples
virtualization, as described earlier. But what about volatile random access memory (RAM) resources
incompatibilities between two applications installed from individual systems in the data center, and
on the same instance of an operating system? then aggregates those resources into a virtualized
Applications commonly share various things with memory pool available to any computer in the
other applications on their system, yet this sharing can cluster. The memory pool is accessed by the
be problematic. For example, one application might operating system or applications running on top
require a specific version of a dynamic link library of the operating system. The distributed memory
(DLL) to function, while another application on that pool can then be utilized as a high-speed cache, a
system might require a different version of the same messaging layer, or a large, shared memory
DLL. Installing both applications leads to what’s resource for a CPU or a GPU application.
commonly known as DLL hell, where one of them  Memory virtualization allows networked, and
overwrites the version required by the other. To avoid therefore distributed, servers to share a pool of
this, organizations often perform extensive testing memory to overcome physical memory
before installing a new application, an approach that’s limitations, a common bottleneck in software
workable but time-consuming and expensive. performance.
Application virtualization solves this 2.) Network Virtualization
problem by creating application-specific copies of all  The term network virtualization is used to
shared resources, as Figure 4 illustrates. The describe a number of different things. Perhaps
problematic things an application might share with the most common is the idea of a virtual private
other applications on its system—registry entries, network (VPN). VPNs abstract the notion of a
specific DLLs, and more—are instead packaged with network connection, allowing a remote user to
it, creating a virtual application. When a virtual access an organization’s internal network just as
application is deployed, it uses its own copy of these if she were physically attached to that network.
shared resources. VPNs are a widely implemented idea, and they
can use various technologies. In the Microsoft
world, the primary VPN technologies today are
Internet Security and Acceleration (ISA) Server
2006 and Internet Application Gateway 2007.

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3.) Storage Virtualization
 The term storage virtualization is also used quite  Development and Testing Environments :-
broadly. In a general sense, it means providing a By usingvirtualization, a developer or tester
logical, abstracted view of physical storage can replicate a distributed environment containing
devices, and so anything other than a locally several systems on a single piece of hardware. This
attached disk drive might be viewed in this light. negates having a bunch of servers sitting around for
 A simple example is folder redirection in the occasional use of developers or testers.
Windows, which lets the information in a folder Virtualization is also useful in test and development
be stored on any network-accessible drive. Much environments in another way. One of the side effects
more powerful (and more complex) approaches of exercising software is that early versions often
also fit into this category, including storage area crash and damage not only the application, but also
networks (SANs) and others. However it’s done, the underlying operating system as well as other
the benefits of storage virtualization are applications in the software stack. To recover, it’s
analogous to those of every other kind of necessary to reinstall all the software. Again, this is
virtualization: more abstraction and less direct areal drag on productivity.
coupling between components.
 Quality of Service :-
4.) Database Virtualization IT organizations must focus on the quality
 Database virtualization is the decoupling of the of service they deliver — how well they keep
database layer, which lies between the storage software infrastructures available and performing
and application layers within the application well.
stack. Virtualization at the database layer allows Fortunately, virtualization, when properly
hardware resources to be extended to allow for managed, can help improve quality of service because
better sharing resources between applications and it removes hardware dependence. By virtualizing
users, masking of the physical location and systems, it is possible to quickly respond to failures
configuration of a database from querying of all types: hardware, network, even virtualization
programs, as well as enable more scalable software itself. It can also be used to pre-emptively
computing. avoid failure by moving workloads off a system that
A. Virtual Data Partitioning is showing signs of problems (memory, disk, and so
B. Horizontal Data Partitioning on).
Given the demands on IT organizations to
 Advantages :- continuously improve their operations in order to
C. Added flexibility and agility for existing achieve business goals, it’s incumbent upon them to
computing infrastructure. explore how virtualization can help improve quality
D. Enhanced database performance. of service.
E. Pooling and sharing computing resources. Companies run many applications that they
F. Simplification of administration and consider mission critical, which is a fancy term
management. meaning that the company relies on these applications
G. Increased fault tolerance. for a fundamental part of their business.

IV. UNDERSTANDING VIRTUALIZATION USE CASES  Simple Failover :-
Virtualization is useful in a number of The hypervisor (Hyper – V) is constantly
scenarios. They range from simple and monitoring each virtual machine’s status, so it’s
straightforward to complex and transformational. relatively straightforward to configure it to start a
Understanding how you want to use virtualization is new instance of a virtual machine should it notice a
critical; because that will dictate which virtualization previously running virtual machine is no longer
solution is most appropriate for you. This chapter present. Because all the hypervisor has to do is start a
goes over some of the main uses of virtualization. new virtual machine based on the VM’s image, the
outage duration of a virtual machine may be mere
 Server Consolidation :- seconds. Obviously, this is a huge improvement over
The first application of virtualization is the minutes to days durations typical of non-
usually server consolidation. In fact, server virtualized system restores.
consolidation is what most people think of when they
consider virtualization. Server consolidation refers to  High Availability :-
taking separate server instances and migrating them High availability (HA) extends the concept
into virtual machines running on a single server. To of simple failover to incorporate an additional
be technically correct, consolidation is also the act of hardware server. Instead of crashed virtual machine
taking a number of separate servers and migrating being started on the same piece of hardware, it is
them onto fewer servers, with multiple virtual started on a different server, thereby avoiding the
machines running on each server.

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problem of a hardware-precluding virtualization Again, efficiency in operation is vital for
failover. replication — just because the data is being moved to
HA provides an extra layer of failover storage location doesn’t mean that keeping the data
protection at the cost of additional virtualization flowing efficiently isn’t important.
software complexity Smart replication software keeps up-to-the-
minute changes flowing to the central location,
 Clustering :- thereby ensuring that an IT organization can quickly
Clustering is designed to ensure that no data locate data assets and use them to rebuild a failed
is lost in the event of a software or hardware failure. system.
Clustering has typically been offered by application
vendors as an add-on to their base product, with some V. RETHINKINGVIRTUALIZATION IN BUSINESS
attendant drawbacks like extra expense, redundant TERMS
solutions, and infrastructure complexity. [ INTEL VERTUALIZATION TECHNOLOGY BRIEF ]
Part of the extra expense reflects the fact  Realizing the general value of the virtualized
that you need extra hardware standing by, with the operating model, Intel addressed virtualization at
mirrored system on standby, ready to take over the foundation - the chip level - where they could
should the primary system fail. You don’t need to be simultaneously eliminate the need for
a genius to recognize that buying a second set of modifications to the hosted operating systems
hardware makes clustering significantly more and provide better performance. The resulting
expensive. However, if you’ve got millions of U.S. Intel® Virtualization Technology (Intel® VT)
dollars’ worth of transactions occurring on your not only provides a consistent approach, but also
system, keeping a redundant server ready may be a opens the door for wider use of virtualization
worthwhile investment. And techniques exist that can concepts such as Real-Time System.
allow you to run other work on the stand-by server  In simple terms, Intel VT adds new instructions,
until it is needed. registers and interrupts management that can be
used by VMM software to manage virtual
 Data Mirroring :- environments. These new capabilities can be
All of the qualities of service mechanisms used to create a VMM that requires no changes
we’ve discussed thus far address how to keep virtual to the hosted operating systems. Consequently,
machines up and running. But what about data? After legacy systems are well supported and the VMM
all, applications inside virtual machines are useless is not dependent on operating system version,
without data — so clearly it’s important to ensure update or patches.
data availability as part of an overall quality of  End users begin to realize the benefits from Intel
service strategy. VT after the suppliers of virtualization software
One way of keeping data available is to modify their products to use the new capabilities.
mirror it. As the name implies, mirroring data means Intel has involved the virtualization community
that data in one place is reflected to another, ensuring in the specification and development
that they are exact copies of oneanother.  Process and work is underway to utilize Intel VT
Mirroring enables real-time consistency in commercial products. For example, Microsoft
between two data stores. This makes it possible to has committed to ongoing support of Intel VT in
immediately shift between one system and another by Windows Servers, and the open source VMM,
attaching the second system to the mirrored data. Xen 3.0, supports Intel VT.
Mirroring achieves this real-time  Intel VT becomes especially attractive when
consistency by feeding a constant stream of data considered in concert with Intel's Dual-Core
changes — whether additions, updates, or deletions technology to provide enhanced performance and
— from one location to another. concurrency of multiple environments to enhance
real-time capabilities. Further advances such as
 Data Replication :- Quad-Core will provide additional capabilities.
Data replication is a second service oriented
toward improving data quality of service. Unlike The Hardware Virtualization Advantage:-
mirroring, which focuses on keeping copies of data  Intel Virtualization Technology provides silicon
consistent in real-time, replication addresses the need based functionality that works together with
to keep complete copies of data available so that they compatible VMM software to improve upon
can be used for system rebuild purposes. software-only solutions. Because this
Replicationis typically accomplished by virtualization hardware provides a new
sending copies of data to a centralized storage architecture upon which the operating system
location, enabling an organization to be certain that it runs directly, it removes the binary translation.
has copies of critical data security stored in case of a Thus it eliminates associated performance
need to recover some specific data assets. overhead and vastly simplifies the design of the

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VMM, in turn allowing VMMs to be written to
100%
common standards and to be more robust.

R a ti o
 The advantage of increase supportability of the 80%
overall virtual machine solution.VMMs running 60%
under the Intel Virtualization Technology can be
40% Performance
fully validated on the hardware, including
certification that they execute directly using the 20% Security
architecture’s full instruction set.
 Intel Virtualization Technology will provide the 0% Benefit
basis for a rich ecosystem of virtualization
solutions that encompass both server and desktop
environments.

VI. BUSINESS SURVEY
 Microsoft, Cisco, Oracle, EMC2 are market- Figure – 5: Result
leading innovative companies has adopted the
virtualization technology by enabling the VII. PITFALLS TO AVOID
application as virtual applications hosted in  In some cases it doesn’t wait any type of
virtual machines are secured across the network protection.
with heightened security, availability, and  Don’t skimp on training.
performance.  Don’t expose for legal issues.
 There are no anymore security issues after  Don’t imagine that virtualization is ―Static‖.
adopting the pull of virtualization.  Don’t skip the ―Boring stuff‖. It’s an overhead
 I highlighted some related survey in below table for cloud infrastructure.
based upon the company and its product and the  Don’t Overlook the Organization.
nature of effect.  Don’t Overlook the Hardware.
 Don’t Overlook the Service Management.
Most Valuable Leading Company  Be Prepared for Even More Virtualization in
Compan Product Performanc Securit Increase Future.
y e y d
Status Issues Benefit VIII. CONCLUSION
[In %] The pull of Virtualization is strong – the
SharePoint +++ Yes 70% economics are too attractive to resist. And for most
Microsof SQL Server +++ None 50% organizations, there’s no reason to fight against this
t Azure ++ None up to pull. Well-managed virtualization technologies can
90% make their world better.
UCS Virtualization technologies provide several
Cisco [Unified +++ None up to important features that make it a powerful tool to use
Computing 73% in a wide range of applications. These include but are
System] not limited to server consolidation, application
Oracle sandboxing, access to varieties of hardware and
Oracle [Database / operating systems, testing, simple system
Web logic +++ Yes 40% administration and quality of service. All these
applications features have made this technology extremely popular
] in academia and industry. A closer look reveals that
Storage although most of them have an operating
EMC2 Application +++ None 60% environment similar to the end-user, they vary greatly
Software in their architecture design, implementation and the
1) In above table I used the +++ strategy for its high better level of abstraction at which they operate.
performance after adopting virtualization. And similarly
(++) for better but not so much as compared to (+++) REFERENCE
strategy. 1] White Paper: Virtualization Overview from
2) There are basically no security issues in adopting VMware. http://www.vmware.com
virtualization technolgy but in some of the criteria I found 2] White Paper: Intel Core Processors –
security issues in some application even if after adopting Understanding Desktop Virtualization.
virtualzation. 3] White Paper By ALAN MURPHY –
3) One main important factor I found is that company’s Virtualization Defined in Eight Different
annual income has been increased. Ways.
4] http://www.virtualizationtechnology.com

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5] Virtualization and Disaster Recovery by J.
Peter Bruzzese.
6] White Paper: Business Value of
Virtualization By HP – AI Gillen, Randy
Perry, Tim Grieser, July – 2008.
7] White Paper: Desktop Virtualization By
NComputing
8] Understanding Microsoft Virtualization
Solutions by Microsoft [2nd Edition].
9] Intel Solution White Paper: Server
Virtualization on Intel Architecture.
10] Technology Brief: Intel Virtualization
Technology by Matt Gillespie.
11] http://www.wikipedia.com/vmware
12] http://www.intel.com/platforms/applied/indp
c/pdf/ARC-Intel-Virtualization-v1.pdf

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