Virtualization for Dummies

Bernard Golden
Margaret Lewis
Tim Mueting
Compliments of
• Create a dynamic data center
• Allocate memory where it’s needed
• Save energy, time, and money
• Improve security and scalability
Learn to:
Virtualization
2nd AMD Special EditionMaking Everything Easier!™
Open the book and find:
• A look at microprocessor
advancements that help
improve virtualization
performance
• An overview of the different
types of hypervisors
• How virtualization helps
reduce power consumption
in the data center
• An explanation of how
memory is virtualized
Bernard Golden is a cloud computing
expert and the author of Virtualization
For Dummies. Margaret Lewis is currently
director of Software Solutions for AMD,
focusing on identifying the next gen
software solutions for AMD products.
Tim Mueting is responsible for AMD’s
virtualization solution strategy.
ISBN: 978-0-470-64412-6
AMD tracking number: 42139-C
Not for resale
Go to Dummies.com®
for videos, step-by-step photos,
how-toarticles,ortoshop!
It seems like everywhere you go these days, someone is
talking about virtualization. Technical magazines trumpet
the technology on their covers. Virtualization sessions are
featured prominently at technology conferences. Basically,
virtualization is a technical innovation designed to increase
the level of system abstraction and enable IT users to
harness ever-increasing levels of computer performance.
• Virtualization’s background — understand where
it came from and better know its moving parts
• Putting virtualization to work — what it can do
for you and your company
• Hardware-assisted virtualization — AMD hard-
ware features that help you get the most out of
your virtualization environment
• Virtualization for the desktop and client — server
hosted desktops help improve manageability,
security, and reduce costs
Understand how virtualization
works and figure out whether
it’s right for you

About AMD
Advanced Micro Devices (AMD) is an innovative technology
company dedicated to collaborating with customers and
technology partners to ignite the next generation of
computing and graphics solutions at work, home, and play.
AMD Opteron™ processors offer uncompromised design and
deliver unprecedented performance-per-watt capabilities,
providing the scalability needed to drive demanding and
data-intensive applications.
These materials are the copyright of Wiley Publishing, Inc. and any
dissemination, distribution, or unauthorized use is strictly prohibited.

Virtualization
FOR
DUMmIES
‰
2ND AMD SPECIAL EDITION
by Bernard Golden, Margaret
Lewis, and Tim Mueting
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Virtualization For Dummies,®
2nd AMD Special Edition
Published by
Wiley Publishing, Inc.
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Hoboken, NJ 07030-5774
www.wiley.com
Copyright © 2010 by Wiley Publishing, Inc., Indianapolis, Indiana
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Table of Contents
Introduction....................................................... 1
About This Book ........................................................................ 2
Foolish Assumptions ................................................................. 2
Icons Used in This Book............................................................ 2
Chapter 1: The Roots of Virtualization. . . . . . . . . . . . . . . .3
Why Virtualization..................................................................... 3
Coming Up with the Concept.................................................... 4
The Hypervisor .......................................................................... 4
Virtualization Makes Hardware More Important................... 7
The Virtualization Revolution in Hardware............................ 7
Chapter 2: Putting Virtualization to Work. . . . . . . . . . . .11
What Virtualization Delivers .................................................. 11
Who Needs Virtualization Technology?................................ 12
AMD Opteron™
Processor: Moving toward Green............... 15
Chapter 3: AMD Virtualization™
(AMD-V™
) Technology . . . . . . . . . . . . . . . . . . . . . . . . . .19
Virtualizing Memory................................................................ 20
AMD-V™
Technology: Better Virtualization through
Better Allocation .................................................................. 21
AMD Technology Helps Manage Memory............................. 22
Extending Virtualization to Devices ...................................... 24
Chapter 4: Virtualization for the Desktop and Client . . . . 29
The Rise of Desktop Virtualization........................................ 30
High-Performance Graphics for Virtual Desktops ............... 30
Client Virtualization: The New Kid on the Block.................. 31
Hardware Extensions Aid Client Virtualization.................... 33
Use Cases for Client Virtualization ........................................ 33
Chapter 5: Ten Great Reasons to Invest
in Virtualization Hardware . . . . . . . . . . . . . . . . . . . . . .37
Create a Dynamic Data Center ............................................... 37
Help Ease Power Consumption and “Stay Cool”.................. 38
Provide Better Security........................................................... 39
Run Legacy Software on Non-Legacy Hardware .................. 39
Develop and Test New Stuff Easily ........................................ 40
Run Multiple Operating Systems on the Same Hardware... 40
Improve Scalability.................................................................. 41
Enhance Your Hardware Utilization...................................... 41
Create a Manageable Upgrade Path....................................... 41
Manage Outages (Expected and Unexpected) Dynamically....42
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Introduction
Virtualization is a technical innovation designed to increase
the level of system abstraction and enable IT users to
harness ever-increasing levels of computer performance.
At its simplest level, virtualization allows you, virtually
and cost-effectively, to have two or more virtual comput-
ing environments, running different operating systems and
applications on one piece of hardware. For example, with
virtualization, you can have both a Linux virtual machine
and a Microsoft Windows virtual machine on one system.
Alternatively, you could host a Microsoft Windows 95 desktop
and a Microsoft Windows XP desktop on one workstation.
In slightly more technical terms, virtualization essentially
decouples users, operating systems, and applications from
the specific hardware characteristics of the systems they use
to perform computational tasks. This technology promises to
usher in an entirely new wave of hardware and software inno-
vation. For example, and among other benefits, virtualization is
designed to simplify system upgrades (and in some cases may
eliminate the need for such upgrades), by allowing users to
capture the state of a virtual machine (VM) and then transport
that state in its entirety from an old to a new host system.
Virtualization is also designed to enable a generation of more
energy-efficient computing. Processor, memory, and storage
resources that today must be delivered in fixed amounts
determined by real hardware system configurations will be
delivered with finer granularity via dynamically tuned VMs.
Already, the combination of software-based virtualization
and AMD’s hardware-based virtualization technology, AMD
Virtualization™ (AMD-V™) technology, allows users to deploy
computing resources in agile, efficient, and cost-effective
ways. AMD is proud to play a pivotal role in virtualization and
thereby help its customers extract ever-increasing value from
their IT investments.
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Virtualization For Dummies, 2nd AMD Special Edition2
About This Book
Virtualization For Dummies, 2nd AMD Special Edition explains
how virtualization works, how it can benefit your organization,
and how the x86 architecture is engineered to better integrate
computing hardware with virtualization software making virtu-
alization faster and more reliable.
The contents of this custom book were provided by and pub-
lished specifically for AMD.
Foolish Assumptions
All authors make assumptions as they write their books. As
we wrote this, a few things we assumed about you included
the following:
✓ You’re an IT decision maker.
✓ You may be the executive officer of a company.
✓ You’re already familiar with computer “lingo.”
Icons Used in This Book
In the margins of this book, you find several helpful little icons
that can make your journey a little easier:
This icon flags information that you should pay attention to.
This icon lets you know that the accompanying text explains
some technical information in detail. You don’t need to know
this stuff to get what you need from the book, but it may be
interesting.
A Tip icon lets you know that some practical information that
can really help you out is on the way. These tips can help save
you time, effort, or money.
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Chapter 1
TheRootsofVirtualization
In This Chapter
▶ Understanding virtualization
▶ Examining the virtualization ecosystem
▶ Looking at x86 server enhancements and multi-core processors
It seems like everywhere you go these days, someone is
talking about virtualization. Technical magazines trumpet
the technology on their covers. Virtualization sessions are fea-
tured prominently at technology conferences. And, predictably
enough, technology vendors are describing how their product
is the latest in virtualization.
Why Virtualization
Technological evolution both drives, and is driven by, ever-
increasing levels of abstraction in hardware and software
architectures. High-level programming languages allow pro-
grammers to implement software without having to pay too
much attention to the operating systems on which it will run.
One job of operating systems is to provide the abstractions
that free programs from the complex and varied details needed
to manage memory and input/output (I/O) devices.
The operating systems that provide this isolation must be
totally cognizant of the hardware on which they reside.
Details like MAC and IP addresses, SAN LUN assignments,
physical memory configurations, processor counts, and
system serial numbers become enmeshed within the OS
05_644126-ch01.indd 305_644126-ch01.indd 3 5/3/10 11:49 PM5/3/10 11:49 PM

state at the time of system installation. This stateful informa-
tion locks the OS to the specific hardware on which it was
installed and complicates hardware fault recovery, system
upgrades, and application consolidation.
Coming Up with the Concept
Hardware and software architects realized that if they could
abstract the hardware as seen by the operating system,
then they could finesse the software’s view of the physical
configuration on which it was installed. This approach is
kind of like the black box model — the software doesn’t
really need to know what’s going on inside the black box
as long as computations sent into the box come back out
with the correct results. The architects called their approach
virtualization, and it turns out to be more complex than you
might imagine.
Complexity arises because an operating system believes it
owns all resources on the hardware on which it runs. More
than that, an operating system doesn’t like to be fooled.
This challenge is made more difficult still, given that the
x86 architecture came into existence before notions of
virtualization became common currency in mainstream
computing.
The Hypervisor
Server virtualization enables you to consolidate many differ-
ent types of workloads and operating systems onto virtual
environments all running on a single hardware platform.
Virtual servers or virtual machines are independent operat-
ing environments that use virtual resources. One of the most
common approaches to virtualization is to use hypervisor
technology. Hypervisors use a thin layer of code in software
to achieve fine-grained, dynamic resource sharing. Today’s
hypervisors provide a high level of flexibility in how virtual
resources are defined and managed and have become a favor-
ite choice for server virtualization.

Chapter 1: The Roots of Virtualization 5
Two types of hypervisors exist. The two types are discussed
in the following sections.
Type 1 hypervisor solutions
You will find that Type 1 hypervisors are typically the preferred
approach for server consolidation because they can achieve
higher virtualization efficiency than Type 2 hypervisors by
dealing directly with the hardware. Type 1 hypervisors provide
higher performance and efficiency, and use hardware assisted
virtualization technology like AMD-V™
technology. Powering
ultrathin notebooks to blade servers, all AMB processors
shipped are designed to use AMD-V features.
Type 1 hypervisors use a thin layer of code to provide resource
sharing within a single hardware platform. In other words, the
hypervisor provides a standard emulated hardware environ-
ment that the guest OS, sometimes referred to as the virtual
machine (VM), resides on and interacts with. The VM encapsu-
lates the guest operating systems and any applications running
on them into a single entity that is isolated from the underlying
hardware. It is because of this encapsulation that the VM can
be migrated from one physical machine to another without any
service interruption.
Not only does this approach support running multiple VMs on
the same hardware, it can also support multiple VMs running
different types and/or versions of operating systems (for
example, completely different operating systems like Windows
and Linux can be run simultaneously on the same physical
server).
Type 1 hypervisor solutions are often used for server con-
solidation to achieve higher levels of resource utilization.
Software development and quality assurance environments
can also benefit greatly from this type of virtualization due to
the ability to allow a number of different operating systems
to be run simultaneously. This can facilitate parallel develop-
ment or testing of software in a number of different operating
system environments, thus leading to quicker, and perhaps
more efficient, testing phases.

Early Type 1 hypervisor solutions experienced some perfor-
mance degradation due to the overhead of the virtualization
software, however, with the introduction of hardware-assisted
virtualization that is built into some of today’s multi-core
processors, and platform improvements, such as expanded
memory and I/O capabilities, this performance degradation
has been minimized. In fact, there is evidence that some
native applications may run as well, if not better, in a virtual
environment due to these improvements.
Operating system virtualization —
Type 2 hypervisor
Type 2 hypervisors run on a host operating system that pro-
vides virtualization services such as I/O device support and
memory management. These services give an application the
illusion that it is (or they are, if there are multiple applica-
tions) running on a machine dedicated to its use. The key
thing to understand is that, from the application’s execution
perspective, it sees and interacts only with those applications
running within its virtual OS, and interacts with its virtual OS
as though it has sole control of the resources of the virtual
OS. However, it can’t see the applications or the OS resources
located in another virtual OS.
Virtualization solutions that use a Type 2 hypervisor are also
referred to as operating system (OS) virtualization, and in
some environments are called containers.
This approach to virtualization is extremely useful if you want
to offer a similar set of operating system functionalities to a
number of different user populations while using only a single
machine. This is an ideal approach for Web hosting compa-
nies: They use container virtualization to allow a hosted Web
site to “believe” it has complete control of a machine, while
in fact each hosted Web site shares the machine with many
other Web sites.
There are some limitations to operating system virtualization,
though. First and foremost, this approach typically limits oper-
ating system choice. Containerization usually means that the
containers must offer the same operating system as the host

OS and even be consistent in terms of version number and
patch level. As you may imagine, this can cause problems if you
want to run different applications in the containers, because
applications are often certified for only a certain OS version
and patch level. Consequently, operating system virtualization
is best suited for homogenous configurations.
Virtualization Makes Hardware
More Important
Even though virtualization is a software technology, it has
the effect of making hardware more important. Removing lots
of servers and migrating their operating systems to virtual
machines makes the remaining servers that support all those
virtual machines vital to running your business.
For example, in an organization that has a “one application,
one server” environment, if a single server goes down, this
inconveniences a single user population. However, virtualiza-
tion is very different. If each server supports multiple virtual
machines, then a server that goes down would inconvenience
multiple user populations. Thus, the hardware can take on
greater importance in a virtual environment.
The greater importance placed upon hardware by virtualiza-
tion technologies is one reason why hardware manufacturers
like AMD have introduced virtualization-ready technologies like
AMD-V technology. AMD-V technology can be found in all AMD
multi-core processors, and other hardware manufacturers have
introduced similar enhancements to support virtualization
implementations.
The Virtualization Revolution
in Hardware
Because virtualization inevitably leads to more apps running
on a single hardware instance, hardware becomes more impor-
tant. And hardware has responded. Well, actually, hardware
manufacturers have responded, but you get the point.

The virtualization-enabling hardware developments break
into two categories:
✓ Virtualization extensions to processors and associated
low-level hardware like network interface cards (NICs).
These extensions allow virtualization to integrate more
closely with the underlying hardware in order to improve
performance and security. For more on these hardware
changes, see Chapter 3.
✓ Form factor changes to servers to support virtualiza-
tion workloads more effectively. Originally, standard
1U servers (sometimes called pizza boxes) were used as
virtualization platforms. These servers typically had one
processor, up to 16GB of memory, and a limited number
of NICs — a design that makes sense in a one application,
one server world. In the new virtualization-oriented world,
though, every one of these capabilities turned into a bot-
tleneck: To run large virtualization workloads, these serv-
ers had too little processing power, not enough memory,
and nowhere near enough network connections. So server
manufacturers have transformed their server designs to
better support virtualization with these design extensions:
• Multi-core processors. Today’s multi-core proces-
sors help to improve utilization and increase VM
density by allowing many virtual machines to share
a single physical server. Additionally, today’s multi-
core processors can be more energy efficient than
single core processors, depending on their usage
and configuration, potentially providing further
energy cost savings.
• Multi-socket servers. Today, single-socket servers
are passé for virtualization. Servers with two or
four multi-core processors, sometimes referred to
as 2P or 4P systems, are the norm.
• Big memory servers. Of all the bottlenecks in virtu-
alization, memory is typically the first encountered.
Solution? More memory. Manufacturers are now
releasing servers with memory capacities of up to
half a terabyte of memory, and, as with all things
hardware, you can expect to see memory capacity
climbing in the future.

• Blade servers. In yet another scheme to pack more
processing into less room, server manufacturers
have pushed all this hardware goodness into blade
servers — servers that contain blades (actually, an
entire server contained on a small plug-in board)
are slotted into a multi-U chassis. Instead of 4 units
in a rack holding four computers, a blade server
can contain 16 or even 32 blade computers in the
same space. Bottom line, more server for a given
amount of rack space, and more virtualization for a
given amount of rack space.

Chapter 2
PuttingVirtualization
toWork
In This Chapter
▶ Understanding what capabilities virtualization offers
▶ Looking at the benefits of implementing virtualization
▶ Going green
This chapter explains what capabilities virtualization offers
and how it can improve day-to-day operations in data
centers. Virtualization is far more than just the latest shiny
thing from Silicon Valley — its capabilities have revolutionized
data center operations and provided enormous cost savings
across companies and industries. Read on to learn more about
the benefits of virtualization.
What Virtualization Delivers
Among other things, virtualization allows you to:
✓ Consolidate workloads to help reduce hardware, power,
and space requirements.
✓ Run multiple operating systems simultaneously, as an
enterprise upgrade path, as a way to leverage the advan-
tages of specific operating systems, or for whatever
reason you can imagine.
✓ Run legacy software on hardware that is newer, more
reliable, and likely more power-efficient.

✓ Dynamically migrate workloads to provide fault tolerance.
✓ Provide redundancy to support disaster recovery.
In the rest of this chapter, we help you understand these
and other benefits of creating and employing virtualized
environments, as well as how many of the risks that used
to be associated with virtualization are being eliminated by
hardware that better supports virtualization software.
Who Needs Virtualization
Technology?
Today, some data centers may have machines running at
only 10 or 15 percent of total processing capacity. In other
words, 85 or 90 percent of the machine’s potential is unused.
However, a lightly loaded machine still takes up room and
draws electricity, so the operating cost of today’s under-
utilized machine can be high.
It doesn’t take a rocket scientist to recognize that this situ-
ation is a waste of computing resources. And, guess what?
With the steady improvement in performance characteristics
of computer hardware, this year’s machines are better than
last year’s, next year’s machine will be better than this year’s,
and so on, for the foreseeable future. Obviously, there ought
to be a more efficient means of matching computing capacity
with load. Fortunately, virtualization can provide that means.
Virtualization enables a single piece of hardware to seam-
lessly support multiple systems, which means organizations
can raise their hardware utilization rates dramatically.
Enabling the dynamic data center
The business world has undergone an enormous transforma-
tion over the past 20 years. Business process after business
process has been captured in software and automated, moving
from paper to electrons.

Chapter 2: Putting Virtualization to Work 13
The rise of the Internet has exponentially increased this trans-
formation. Using the worldwide connectivity of the Internet,
companies want to communicate with customers and part-
ners in real-time. Naturally, this too has accelerated the move
to computerized business processes.
Over time, organizations have adopted a variety of hardware
and software systems throughout the enterprise. Today’s
complex data-server environments have grown exponentially,
leaving companies with larger and more rigid data centers.
Not only can it become cost-prohibitive to administer these
data centers, it can also be difficult to achieve optimal value,
return on investment (ROI), and return on assets (ROA).
Virtualization enables organizations to make more effective
use of their computing resources and to move legacy software
to newer, more efficient hardware platforms. The ability to
run different operating systems and applications on the same
physical server lets organizations consolidate the workload
placed on servers. Virtualization partitions a server into
several virtual machines, each able to run its own separate
operating system and application environment. This moves
businesses away from a “one server, one application” model
toward an infrastructure that lets a business manage its
servers across a heterogeneous environment far more
effectively.
System administration
costs mount
Computers don’t operate all on their own. Every server
requires TLC from system administrators. Common system
administration tasks include monitoring hardware status,
replacing defective hardware components, installing operat-
ing system (OS) and application software, installing OS and
application patches, monitoring critical server resources
like memory and disk use, and backing up server data
to other storage mediums for security and redundancy
purposes.

As you can imagine, these tasks can be pretty labor intensive.
System administrators — the people who keep the machines
humming — don’t come cheap. And, unlike programmers,
system administrators are usually co-located with the servers,
because they need to access the physical hardware.
Virtualization enables an organization to streamline and
automate a host of complex processes, respond to changing
business requirements, and achieve the flexibility required to
compete in today’s global economy. This can often result in
a reduction in the costs associated with the management and
administration of the data center because for many organiza-
tions, system and network administration is an expensive and
unwieldy task. Consider that, as the computing environment
becomes more complex, IT staffing needs and tasks will likely
increase in both number and complexity. However, virtualiza-
tion can tip the balance back in favor of the enterprise. A well-
planned virtualization strategy can reduce the time it takes for
IT staff to manage the server infrastructure. This leaves hard-
ware specialists, programmers, and other professional staff
free to handle more strategic work.
Green initiatives seek better
energy efficiency
Years ago, power costs factored into strategic thinking at
about the same level as what brand of soda to keep in the
vending machines. Companies generally assumed that electri-
cal power would be cheap and endlessly available, so it was
not a major factor in strategic plans.
The assumption regarding availability of reliable power was
challenged during the California power scares of a few years
ago. Although later evidence caused re-evaluation of whether
there was a true power shortage, the events caused many
companies to consider whether they should look for ways to
be less power dependent.
Furthermore, the impact of the green revolution has encour-
aged many companies to look for ways to reduce the amount
of energy they consume.

One way in which companies have done this is by turning
their focus to their data centers. To show the level of concern
about the amount of energy being consumed in data centers,
consider these facts:
✓ According to a study performed by researchers from the
Lawrence Berkeley National Laboratory and facts pub-
lished by the U.S. Department of Energy, data centers in
the U.S. doubled their energy consumption between 2000
and 2006, and are likely to double that again by 2011.
In addition, the U.S. Environmental Protection Agency
(EPA) found that in 2006, cooling costs for data centers
accounted for 1.5 percent of the total energy consumed
in the U.S.
✓ Based, in part, on the results of an earlier study by this
group, the U.S. EPA has convened a working group to
establish standards for server energy consumption and
plans to establish a new “Energy Star” rating for energy-
efficient servers.
The cost of running a large number of servers, coupled with
the fact that many of the machines filling up data centers are
running at low utilization rates, means that a company that
implements virtualization technologies may be able to reduce
the total number of physical servers, and thereby reduce its
overall energy costs. This is another way in which virtualiza-
tion can help.
AMD Opteron™
Processor:
Moving toward Green
A leading factor in why companies are moving to virtualiza-
tion is to help reduce energy consumption. Big data centers
can use incredible amounts of power, and anything that helps
reduce power is welcome.
Although it may seem that the power savings for one chip
would be relatively insignificant, keep in mind that today’s
data centers can contain thousands of machines. Even a virtu-
alized data center, where many physical machines have been
converted to guest virtual machines, can contain hundreds of
physical servers.

AMD is doing its part to help reduce power consumption, but
not at the cost of decreased performance. AMD has included
a number of features within its AMD Opteron processors,
including AMD-V™
technology, hardware assisted virtualiza-
tion technology, and AMD-P, a suite of power management
capabilities that can dynamically minimize power usage of the
overall processor, individual cores, and the logic within each
core. For more info on AMD-P, see Table 2-1.
Table 2-1 The AMD-P Suite of Power
Management Capabilities
Capability Benefit
AMD CoolCore™
Technology
Can reduce energy consumption
by turning off unused parts of the
processor.
AMD Smart Fetch
Technology
Helps reduce power consumption
by allowing idle cores to enter a halt
state, causing them to draw even
less power during processing idle
times, without compromising system
performance.
Independent Dynamic
Core Technology
Enables variable clock frequency for
each core, depending on the specific
performance requirement of the appli-
cations it is supporting, helping to
reduce power consumption.
Dual Dynamic Power
Management (DDPM)
Technology
Provides an independent power
supply to the cores and to the memory
controller, allowing the cores and
memory controller to operate on differ-
ent voltages, depending on usage.
AMD PowerCap manager Provides the ability to put a cap on the
P-state level of a core via the BIOS,
helping to deliver consistent, predict-
able power consumption of a system.
AMD C1E A sleep state invoked when processor
cores are at idle that can equate to
significant power savings in the data
center.

AMD-P enables the processor to provide the needed perfor-
mance while helping reduce power consumption both directly
and indirectly: direct power consumption by the processors,
and indirect power consumption required to deal with the
heat thrown off by those processors. Together, those tech-
nologies can help enable cutting-edge energy efficiency.
By running AMD Opteron processors with AMD-V technol-
ogy and AMD-P in a virtualized environment, users can save
energy in two ways:
✓ By dynamically adjusting to processing demands, each
machine can tailor the amount of energy needed to the
specific job. Thus, users can save on overall energy con-
sumption by using energy on an as-needed basis.
✓ Using less energy means less heat in the chip (chips
generate heat as they process information). By reduc-
ing the heat generated by the machine, users will need
less air conditioning in the data center, further reducing
energy consumption (and saving even more money
on energy costs!).
So not only can AMD Opteron processors help to make your
virtualization systems run more effectively, they can make
your data center run more efficiently.

Chapter 3
AMDVirtualization™
(AMD-V™
)Technology
In This Chapter
▶ Virtualizing memory
▶ Digging into AMD Virtualization technology
▶ Examining I/O virtualization technology
Virtualization originally was a software innovation that
required a very smart hypervisor to mediate resource
contention between physical hardware resources like the
computer’s processor, memory, network, and storage. Even
though the virtualization software was very smart, naturally
people began to think how much better it could be if it were
only . . . higher performance! And so AMD set to work to see
how to make virtualization even more efficient. Their innova-
tions in areas like AMD Virtualization (AMD-V) technology and
I/O virtualization with IOMMU, offer better performance due
to hardware optimization.
As individual virtual machines improve, more of them can be
supported on a given piece of hardware; in other words, if
virtual machine performance goes up, more virtual machines
can be squeezed onto one server, thereby achieving higher
virtual machine density.
Virtual machine density refers to the ratio of virtual machines to
physical machines. The higher the number of virtual machines
that can be supported on a physical system, the higher the
virtual machine density. Put another way, the higher the den-
sity, the lower the number of physical machines required to
run an organization’s virtual systems.

Performance can be another key element when it comes to
virtual machine density, but raw performance doesn’t always
result in optimal throughput and energy efficiency. For vir-
tualization solutions running many disparate workloads on a
single physical server, it is often important to balance raw per-
formance and energy efficiency — also known as performance-
per-watt — as well as factoring in overall system price, when
assessing the bottom line of any virtualized solution.
Virtualizing Memory
Long before computer scientists came up with the notion of
virtualizing an entire system, architects had already invented
techniques to virtualize memory management. The Atlas com-
puter at the University of Manchester was the first system
to incorporate virtual memory technology. Virtual memory
technology lets a system with a limited amount of physical
memory look much larger to application software. To create
this illusion, the OS stores the full memory image of the appli-
cation and its data on the system’s hard drive, and transfers
required pieces of this image into the system’s DRAM memory
as the program executes.
To translate the virtual addresses seen by each application
into physical DRAM memory addresses, the system relies on
a map (known as a page table) that contains references linking
chunks of virtual memory to real memory. Contemporary x86
processors include hardware features known as translation
look-aside buffers (TLBs) that cache the translation refer-
ences for recently accessed chunks of memory, thus speeding
up the process. TLBs play a role in almost all memory refer-
ences, so the manner in which they perform their translations
can play a significant role in determining overall system
performance.
Architects soon learned that TLB design can seriously impact
multitasking systems operations. Most tasks in such systems
have unique page tables, which forces the operating system
to reset (or, more colorfully, “flush”) the TLB each time it
switches from one task to another. Then, as the new task
executes, its page table entries fill up the TLB, at least until
the next task switch. This constant flushing and reloading can
really eat into performance, especially if each task runs for
only a few milliseconds before the next switch.

(AMD-V™
) Technology 21
AMD-V™
Technology: Better
Virtualization through
Better Allocation
Clearly, a more efficient approach to managing hardware
resources would help overall virtualization performance.
To that end, AMD introduced AMD-V technology with its
Dual-Core AMD Opteron™
processors in 2006. AMD-V technol-
ogy is designed to improve virtualization performance with
processor-based hardware enhancements.
AMD-V technology also leverages Direct Connect Architecture
with an integrated memory controller to provide fast and effi-
cient memory management.
So how did this play out with respect to that pesky memory
management? AMD processor architects added a new, virtual
machine (VM) specific tag called an address space identifier
(ASID) to the TLBs in the AMD Opteron processors. This
concept is known as a tagged translation look-aside buffer,
or tagged TLB.
Each VM has a unique ASID value, known only to the hyper-
visor and the TLB hardware. The ASID is invisible to the guest
OS, thus eliminating the need to modify the guest, preserving
the virtual illusion and avoiding any performance degrada-
tion. Figure 3-1 illustrates the tagged TLB concept.
VM 1 runs on the CPU and
loads additional data from
memory
As VM 3 takes control and
loads its data, other TLB
data remains
So when VM 1 takes control
back the data it needs is
there … resulting in
better performance
VM 1 VM 2
AMD Non-AMD
VM 3
VM 1
VM 3
VM 1
VM 4 VM 5 VM 6
Hypervisor (VMM)Hypervisor (VMM)
HT 3
HT 1
HT 2
AMD Opteron™
Tagged TLB
Cache lines
Memory
Controller
Legacy x86
Architecture
Un-Tagged TLB
Cache lines
Front-sideBus
Figure 3-1: Tagged translation look-aside buffer.

AMD Technology Helps
Manage Memory
One of the most important tasks for a hypervisor is memory
management. The ability to keep track of the memory for indi-
vidual processes within a virtual machine is critical for virtu-
alization. Even more important is to ensure that each virtual
machine’s overall memory is managed. The latter task may
be referred to as keeping track of virtual machine state — the
settings of all critical system variables at each moment in time.
Shadow paging
Software-only virtualization solutions use a technique called
shadow paging. Shadow paging uses stored information
about the physical location of guest memory in shadow page
tables and manages these structures in the hypervisor. Under
shadow paging, the hypervisor intercepts guest page table
updates to keep the shadow page tables in synch with the
guest page tables.
Starting with the first Quad-Core AMD Opteron processors,
AMD implemented a hardware optimization to memory manage-
ment called rapid virtualization indexing (RVI). RVI translates
memory addresses from virtual to physical, but unlike shadow
page tables, which perform these translations in software, RVI
performs the memory translation in the CPU (see Figure 3-2).
Understanding the flow
of memory
To understand what rapid virtualization indexing accom-
plishes, it’s important to understand the flow of memory in a
virtualized environment:
1. The virtual machine operating system has its own vir-
tual memory that enables the system to “pretend” its
total available memory is larger than is really available.
Page tables swap memory back and forth onto disk to
enable this. (This is called guest virtual memory.)

(AMD-V™
) Technology 23
2. The virtual machine has actual memory that this vir-
tual memory is swapped into and out of as needed.
In a virtualized environment, this actual memory is
managed by the hypervisor and is, in fact, also virtual.
(This is called guest physical memory.)
3. The hypervisor itself manages a pool of memory that
may be larger than the physical memory available on
the underlying server. It has pages that it swaps back
and forth with the disk to support this virtual memory.
4. Finally (at last!) there is the physical memory on the
hardware system, which is where actual processing
occurs. (This is called host physical memory.)
Rapid virtualization indexing (RVI) provides this hardware
mechanism to determine the physical location of guest
memory by walking an extra level of page tables — called
nested page tables.
Guest Linear
Hypervisor translates a page in guest virtual address space to machine
physical space through a two-level translation
– First, map guest virtual address to guest physical address
– Then, map guest physical address to machine physical address
0
Guest Physical
gCR3
pagedby
paged by
pagedby
pagedby
nCR3
nCR3
TLBEntry
the VMM’s CR3
gCR3
CR3 (used by VMM)
0
VMM Host Linear
0
System Physical
0
PTnPT gPT
gPT
nCR3
Figure 3-2: Design of AMD’s Rapid Virtualization Indexing.

In a native system, the operating system maintains a mapping
of logical page numbers to physical page numbers in page
table structures. When a logical address is accessed, the hard-
ware walks these page tables to determine the corresponding
physical address. For faster memory access, the x86 hardware
caches the most recent mappings in its translation lookaside
buffer (TLB).
In a virtualized system, the guest operating system maintains
page tables just like in a native system, but the hypervisor
maintains an additional mapping of the guest physical page
numbers to host physical page numbers in the shadow page
table structures.
RVI enables the hypervisor to maintain this guest-physical to
host-physical mapping in a second level of page tables, called
nested page tables in hardware.
When a logical address is accessed, the hardware walks the
guest page tables as in the case of native execution, but for
every guest physical page accessed during the guest page
table walk, the hardware also walks the nested page tables
to determine the corresponding host physical page address.
This eliminates the need to maintain shadow page tables and
synchronize them with the guest page tables.
Overall, this can help reduce the overhead of accessing
memory, thereby increasing system performance. The extent
of this performance increase is somewhat dependant on the
type of workload the virtual machine is executing; memory-
intensive applications see more performance improvement
than applications that aren’t heavily dependent on memory
access. But by and large, moving the memory access func-
tions into hardware can improve performance, which in turn
can improve virtual machine density.
Extending Virtualization
to Devices
With AMD-V technology, AMD has created ways to improve
the performance of network, storage, and graphics in a virtu-
alized environment. AMD has also introduced technology for

(AMD-V™
) Technology 25
I/O virtualization which resides in the AMD chipset. AMD-V
uses an I/O Memory Management Unit, often called IOMMU,
to control how a device accesses memory. The IOMMU also
provides a mechanism to isolate memory accesses by these
devices, thereby helping to improve the security in a virtual-
ized environment
Locating memory
In order for information to flow back and forth to these input/
output devices (this is where the IO in IOMMU comes from),
it first must be moved to memory that is accessible by the I/O
device. Each I/O device connected to a computer has its own
specific location in the system memory. The operating system
knows just where that memory is, so when it wants to send
data, say, across the network, it transfers data from the proces-
sor’s memory to the I/O device’s memory, where the I/O device
can access it and send it on its merry way. When data returns,
the I/O device puts it into its assigned memory location, where
the OS grabs it and transfers it into the processor’s memory,
where it can be processed.
This gets complicated in a virtualized environment. The guest
operating system directs I/O-bound data to where it thinks the
I/O device can grab it, but the virtualization hypervisor cleverly
intercepts the attempt by the guest OS to write to physical
memory and maps it through its own memory and then onto
the actual physical memory that the I/O device is attached to.
The hypervisor must keep track of and map all the different
guests’ virtual I/O memory locations and constantly swap the
virtual representations of the guests’ I/O memory locations
into the actual physical I/O memory. As should be pretty
clear, this requires really, really smart hypervisor software
so that all I/O interactions can be kept straight. After all, you
wouldn’t want your CRM system to be reading data from your
DNS (domain name service) system, would you?
Of course, one wouldn’t use the term “kept straight” in a
complex computer science topic like virtualization — it
sounds so . . . casual. By leveraging AMD’s IOMMU, systems
ensure data integrity (“keep data straight”) as well as enforce
security, since the functionality isolates individual VM I/O
from one another. One VM can’t access the I/O memory
locations of another VM.

With I/O memory mapping, the hypervisor must perform this
task efficiently — very efficiently. Doing so is particularly
important because I/O is critical for overall system
performance — after all, no computer operates without
accessing data on a hard drive. In today’s computing world,
applications typically interact with users or other systems
across a network. So I/O performance is an important area
that really needs optimization to ensure acceptable perfor-
mance, and, of course, good virtual machine density.
Chipsets that work with you
The processor and the chipset really are partners and must be
designed to work together. AMD has delivered the AMD SR56x0
chipset, which integrates chipset-resident functions into its
AMD Opteron processor-based platforms and is enabled with
I/O virtualization technology (IOMMU) for robust support for
memory- and I/O-intensive environments.
Understanding IOMMU
AMD has taken the lead in moving functions originally per-
formed by the hypervisor in software into hardware, and
IOMMU is no different. In fact, IOMMU takes advantage of
some of the same architectural approaches used in shadow
page tables.
In essence, IOMMU subdivides the I/O memory associated
with an I/O device and allows a hypervisor to create dedi-
cated subsections of the memory that may be assigned to
virtual machines (see Figure 3-3). In this way, each virtual
machine has a section of memory dedicated to its I/O use,
which means the hypervisor can set up the original dedicated
connection, and then let the virtual machine communicate
directly with the I/O device without needing to be involved.
This can reduce the software processing overhead and
improve performance.
Subdividing the memory assigned to an I/O device presents
some challenges: how to keep track of each of the subdivisions,
how to ensure that the I/O device places the appropriate data
into the right memory subdivision, and how to ensure that only
the right virtual machine accesses that subdivision to get its
assigned data.

(AMD-V™
) Technology 27
CPU
HyperTransport™
technology link
HyperTransport™
technology link
DRAM
PCIe™ bus
Memory Controller
IOMMU
I/O Hub
TLB IOMMU
I/O Hub
TLB
LPC
PCI
SATA
Integrated
Peripherals
I/O
Device
I/O
Device
IOTLB
I/O Device
PCIe™ busPCIe™ bus
Figure 3-3: How IOMMU works.
How does IOMMU meet this challenge? Remember our old
friend the translation look-aside buffer (TLB)? Well, IOMMU
takes advantage of TLBs to isolate the various subdivisions
of the I/O memory. Furthermore, it uses a Domain ID to keep
track of the assignments between particular memory areas
and the guest virtual machines on the system.
By implementing IOMMU, a hypervisor can reduce the
number of steps required to get data from a virtual machine
out to a physical I/O device. By bypassing some steps, the
system will have to execute fewer software instructions,
which can raise system performance, and, ultimately, drive
higher virtual machine density.

Chapter 4
Virtualizationforthe
DesktopandClient
In This Chapter
▶ Examining how virtualization is key to the future of computing
▶ Tracing the rise of client device virtualization
▶ Looking at different types of client virtualization
▶ Understanding how hardware helps client virtualization
It may seem like all the virtualization fun is centered
on servers located in the data center. But have no fear!
Virtualization has come to client devices (more informally
known as desktops and laptops), and can offer the same types
of benefits that server virtualization offers — and a few others
besides.
The evolving concept of a virtualized desktop is evidenced by
the recently formed Virtual Desktop Infrastructure Alliance
that helps IT administrators create and manage “desktop vir-
tual machines” on servers within data centers. End-users may
access these desktop environments at any time and from any
place, using thin client devices (or thin client access utilities
on more fully configured systems). Even old, underpowered
systems can use the Remote Desktop Protocol (RDP) to access
more powerful virtual PC desktops loaded with up-to-date
software versions.
This approach to client deployment can lead to lower sup-
port expenses as well as hardware acquisition costs because
the virtual PCs reside on centralized servers in a managed IT
environment. This can eliminate the need to visit the client’s
actual desktop system for most maintenance activities, which
can help reduce IT personnel costs and overhead.

The Rise of Desktop
Virtualization
Client virtualization is a growing trend — but it’s based in
technology that has been available for a number of years.
The ability to display a desktop remotely, known as desktop
virtualization, has been part of Windows for at least a decade,
but most organizations found the capability too limited for
general use. Two primary problems held back the spread of
desktop virtualization:
✓ Poor overall performance. Trying to send an entire
desktop across a network is a challenge, and the early
protocols to support desktop virtualization weren’t
efficient enough to provide sufficient performance,
resulting in slow desktop refreshes, jerky motions —
in short, unsatisfactory experiences.
✓ Poor graphics performance. Even after more efficient
protocols became available, graphics-rich programs still
suffered because of the difficulty of transmitting rapidly
changing output.
However, the rise of server virtualization, which made hosting
desktops in the data center easy and efficient, enabled new
developments in desktop virtualization.
High-Performance Graphics
for Virtual Desktops
So what about graphics performance in this new world of
Virtual Desktops? Users demand advanced graphics features
like standard USB connectivity, multi-monitor support, and
complex streaming and 3D support. Well, here is another
example of where AMD is leading the charge when it comes to
graphics and virtualization.
A relatively new protocol that enables remote access to high-
performance graphics applications in the data center is evolv-
ing called PC-over-IP (PCoIP). The PCoIP protocol compresses,

Chapter 4: Virtualization for the Desktop and Client 31
encrypts, and encodes the entire computing experience at the
data center and transmits only the changing display pixels
across a standard IP network to stateless PCoIP technology
enabled devices. This greatly reduces the amount of network
bandwidth required to feed the end-user’s thin client system
while still providing a constant and robust graphics update.
PCoIP technology is delivered in both hardware and software
based implementations, and both types of solutions are now
supported by AMD’s FirePro™
line of ATI Graphics cards.
An example of these devices is the ATI FirePro RG220 card.
This card supports the PcoIP protocol and can be installed
in servers residing in the data center. Dedicating a graphics
card per client, along with support for PcoIP, can provide
high-quality 2D, 3D, and complex graphics support.
Some AMD FirePro graphics cards, working in conjunction
with AMD Virtualization™
(AMD-V™
) technology, can support
a new feature called direct mapping. Direct mapping is a way
in which a virtual machine (VM) can be directly mapped to
a graphics driver. This now gives each VM its own fully dedi-
cated graphics card to use for full, no-compromise graphics
performance. Direct mapping coupled with multiple FirePro
RG220s allows for a single server to create multiple virtual
machines with full graphics performance and full multiple
remoting connections.
Client Virtualization: The New
Kid on the Block
One drawback to desktop virtualization is obvious: To use it
you must be connected to the network. What about virtualiza-
tion in environments in which you aren’t connected to the
network? A new form of client-oriented virtualization, termed
client virtualization (very creative, eh?) has sprung into being
and is being widely deployed.
In this form of virtualization, rather than the client virtual
machine residing in the data center, it sits on the client device
and can be used locally — that is, without a network connec-
tion to the data center.

Understanding client
virtualization
Just as server virtualization abstracts an operating environ-
ment (a combination of an operating system, software, and
data into a virtual machine), client virtualization does the
same thing — just for an end-user device like a desktop or
laptop computer.
Client virtualization abstracts dependence on physical
resources so that a complete operating environment may be
encapsulated in a virtual machine — thereby enabling one
client device to support multiple virtual machines, which
makes client virtualization a very interesting proposition,
indeed.
What client virtualization
provides
Client virtualization allows a single physical device to support
multiple operating environments. Each operating environment
is comprised of an operating system, application software,
and data associated with that virtual machine.
With client virtualization, one can support several different
virtual machines on that one device.
Examples of the types of virtual machines that can be hosted
on one device include:
✓ Identical virtual machines. Suppose you want to offer
users the ability to run different versions of an applica-
tion software package. You could provide several differ-
ent client machines, but that turns a lightweight laptop
into a burden of several different machines — a real drag.
Instead, you put several different virtual machines onto
one laptop and, voila, system flexibility without back
strain!
✓ Virtual machines with different operating system ver-
sions. Suppose you want to run the same application soft-
ware on different versions of the same operating system

to test compatibility. See the previous paragraph — client
virtualization allows system flexibility and your back still
stays unstrained!
✓ Different operating systems on the same physical
device. There are many scenarios where you might want
to run, say, Windows and Linux on the same device.
Before virtualization, there was no way to accomplish
this. Even today, with Type 2 virtualization, laptops
strain to support virtualization.
Hardware Extensions Aid
Client Virtualization
Given that most laptops don’t offer the same kind of form
factor developments outlined in Chapter 1 of this book, highly
efficient virtualization is a must for successful client virtual-
ization. Because most laptops are limited to 4 GB of memory,
hardware extensions that help to improve efficiency and
performance are a real help. In fact, many client virtualization
solutions require hardware-assisted technology.
AMD long ago recognized virtualization on the client and
the desktop and has included AMD-V technology in all the
latest AMD processors for server, desktop, and mobile
platforms.
Use Cases for Client
Virtualization
The flexibility client virtualization offers simplifies many use
scenarios. The following sections discuss some common use
cases for client virtualization.
There are undoubtedly more client virtualization benefits that
will be discovered in the future as the technology is more
widely adopted. It’s safe to say, though, that the established
practices associated with personal computing are about to
undergo a transformation, leading to more efficiency and
lower costs.

Software engineering
Software engineers traditionally face a difficult work situation.
Many software applications require multiple systems, one
running Windows, another Linux, yet another operating as
a backend Web server. Each of these systems may require
two or more versions, reflecting different versions of operat-
ing system, application software, and configurations. Trying
to keep these installed and configured properly in a tradi-
tional environment hampers productivity, because lots of
time is spent in installing and configuring different software
products — not to mention tying up lots of expensive
equipment.
With client virtualization, a software engineer can have many
different virtual machines stored on a client machine’s disk,
and bring up only the necessary ones to program or test a
specific application topology. Instead of trying to keep track
of many different pieces of hardware, the necessary virtual
machines can be brought up in minutes. There’s another
advantage, too. In today’s world of telecommuting and travel,
software engineering’s traditional practice of using hardware
for all the different parts of an application is unworkable; with
client virtualization, a software engineer can be productive
anywhere. Magic!
Software testing
Just as software engineers can be relieved of a great deal
of repetitive work when virtual machines replace physical
machine, so too can software testers. In fact, software testers
probably realize even more benefits because of the highly
dynamic application configurations typical of software testing.
Another benefit of client virtualization for software testing is
the support it offers for reproducing problems. In the past, a
software tester who observed a bug would need to describe
how the system was configured and what steps were taken with
the software. With client virtualization, the virtual machine in
which the problem was observed can be stored and provided
to the software engineering team, which can immediately
observe the problem without trying to reproduce it.

Mixing personal and
work environments
It’s no secret: Folks live online today. Each of us uses social
media applications, stores digital media like photos and
music, runs personal apps — they’re all part of our modern
digital life.
Unfortunately, online activity can cause problems. If you’re
using your business-issued laptop, loading non-approved
software can be against company policy. Even worse, your
personal software may have operational conflicts with
software necessary to your business activities. This, of
course, doesn’t even address the question of whether you
want your personal work intermixed with your business
activities.
Most companies want to have a standard “image” of an
approved combination of operating system, applications, and
configurations. Allowing personal applications to be installed
or Web sites accessed can compromise business application
stability and expose the company to risk.
Client virtualization, with the ability to support multiple
virtual machines can mitigate these problems. By “locking
down” the official business virtual machine and offering a
second virtual machine for personal use, companies can
avoid issues of application conflict or corporate liability.
Likewise, individual users can use a personal virtual machine
during non-business hours, secure in the knowledge that
personally useful applications can be operated with no
danger of conflict with the business virtual machine.
Training
Training departments have a common problem: Every student
requires a fresh environment to interact with, and setting up
a fresh environment for every student is expensive and time-
consuming.

Client virtualization can reduce the amount of time spent in
this repetitive process, because a fresh virtual machine with
a software configuration set up for the student to begin work
can be created and deployed at will. One virtual machine,
configured properly, can be installed on every student’s PC,
saving enormous amounts of work and, just as important,
avoiding the inevitable mistakes that can occur when a
manual process is carried out time and again.
System migration
Last — but not least — is the way that client virtualization
can assist in system migration. Most corporate environments
replace PCs every three or four years. Each of these replace-
ments requires a costly backup and data migration of the
existing client machine (not to mention these migrations
often lose personally installed applications or data — see
the “Mixing personal and work environments” section).
Instead of this costly process, imagine how easy a system
migration can be if all that is required is for a virtual machine
on the old system to be backed up to a central server and
then deployed onto the new client machine.

Chapter 5
TenGreatReasonstoInvest
inVirtualizationHardware
In This Chapter
▶ Getting more secure
▶ Saving money
▶ Improving scalability
It’s here — the end of the book. And like all For Dummies
books, this one includes a chapter listing ten things worth
listing.
In this chapter, we’ve collected ten great reasons to use
hardware virtualization in your technology space.
Create a Dynamic Data Center
Virtualization helps you break the “one application per
server” model, while defining your data center by logical
boundaries rather than physical boundaries.
To date, most data centers operate with excess capacity
so they can handle increases in demand as and when they
arrive. However, when systems sit idle, they gobble up
power, produce heat, take up space, and waste money.
In a virtualized data center, as demand for a particular appli-
cation increases, you may be able to move those virtual
machines (VMs) to a physical server with excess capacity to
handle the workload. Conversely, when demand decreases,
you simply reallocate your virtual resources accordingly.

And because workloads increase and decrease all day long at
undetermined times, each of the various VMs on a physical
server can take advantage of any extra capacity without direct
human intervention. The result is that you can build a data
center with fewer total resources, because resources can be
used as needed instead of being dedicated to single applica-
tions or sitting and waiting until the next spike in demand.
At its core, virtualization isn’t really about virtual anything —
it’s about the dynamic allocation of resources. Yes, the basic
unit of virtualization is a virtual machine, but it’s what a vir-
tual machine does that is so useful.
Virtualization enables you to allocate resources where you
need them, when you need them, from an aggregate pool of
resources. You can look at the aggregate demand of your envi-
ronment, build out sufficient capacity to handle that demand,
and then pull as necessary from that capacity and be able
to handle multiple operating systems, servers, and applica-
tions. This can save money on your total hardware investment
(including potential power, heat production, and resultant cool-
ing requirements, real estate needs, and so on). It may also free
up your IT staff to be more productive — instead of spending
all day managing hardware, they can focus on end-user needs.
Help Ease Power Consumption
and “Stay Cool”
Virtualization provided the capability for multiple virtual
machines with multiple operating environments to share a
single AMD Opteron™
processor-based server. A range of
applications, hosted under a variety of environments such
as the Microsoft Windows, Linux, and Sun Solaris operating
systems, can coexist on a single “real” machine. Each appli-
cation executes within its own container, or virtual machine
(VM), unaware that it might in fact be one of many applica-
tions under one of many operating systems residing on a
single piece of hardware.
Depending on the nature and duty cycle of the individually-
hosted applications, a single AMD Opteron processor-based
system can run hundreds of virtual machines. This results in
a significant savings when considering the amount of power

Chapter 5: Ten Great Reasons to Invest in Virtualization Hardware 39
it would take to run the same number of physical servers.
These savings in real power consumption are amplified when
you factor in the power needed (approximately 50 percent
of required system power) to remove heat from the system.
In addition to these forms of power savings, AMD is doing its
part to reduce the power consumption within the processor,
while delivering real-world performance and a full set of fea-
tures. AMD Opteron processors come with the AMD-P suite of
power management capabilities that dynamically minimizes
power usage of the overall processor, individual cores, and
the logic within each core, based on application needs and
server workloads.
AMD-P enables the processor to provide the needed perfor-
mance while reducing power consumption, which in turn
produces less heat. Therefore, AMD-P technologies help
control costs on two fronts: direct power consumption by
the processors, and indirect power consumption required
to deal with the heat thrown off by those processors.
Together, those technologies can help enable cutting-edge
energy efficiency. That can be a major competitive advantage
for cloud service providers, whose data centers typically
house large volumes of power-hungry servers.
Provide Better Security
Virtualization allows you to keep sensitive corporate data
separate from end-user data, and one set of end-user data
separate from another, even though they reside on the same
physical machine. If you assign separate VMs to handle those
data, you could give one VM with end-user tasks access to
downloads and other higher-risk operations, while the VMs
that handle other end-user data and sensitive and/or critical
data stay securely out of reach.
Run Legacy Software on
Non-Legacy Hardware
Many enterprises still have applications that will only run on
older operating systems The last thing they want to do is try

to keep old hardware around and useable just to run older
applications.
A virtualized environment can enable a VM designed to
emulate legacy hardware and allow you to run the necessary
operating system and legacy software — all of this can run
on the latest and greatest (and reliable) new hardware.
Develop and Test
New Stuff Easily
Software developers can create virtual environments to run
multiple operating systems, or even different versions of the
same operating system, to test software.
Similarly, if you’re part of an enterprise considering rolling
out new software, you can limit its deployment to one secure
piece of your infrastructure (by installing it on a VM) and
see how it behaves and how your users respond before you
deploy it enterprise-wide.
Virtualization allows the rapid deployment of new VMs, along
with the rapid relocation of VMs from one physical server
to another. New applications can proceed from concept to
development to deployment with fewer delays.
In addition, many applications that run on real (that is to say,
nonvirtual) machines may require at least three dedicated
systems: one for development, one for normal execution,
and one to back up the system usually used for execution.
Virtualization enables organizations to run the same work-
loads on fewer physical systems, which can help the IT staff
be more productive and more responsive to user needs.
Run Multiple Operating Systems
on the Same Hardware
Many enterprises use multiple operating systems. It’s not
uncommon to run Linux, Microsoft Windows, and Solaris

Chapter 5: Ten Great Reasons to Invest in Virtualization Hardware 41
within one organization. Virtualization lets you do this more
smoothly on the same hardware, rather than needing at least
two discrete hardware installations.
Improve Scalability
Enterprises grow. With virtualization, responding to the
changing needs of your environment doesn’t need to follow
the old way of “throwing more hardware at the problem.”
Instead, you can scale your environment much more dynami-
cally, responding, for example, to growth in the user base of
two server/application combinations with only one new piece
of hardware virtualized to account for where you need the
resources.
Enhance Your Hardware
Utilization
With virtualization, you’re managing the aggregate demand
of your enterprise instead of the demand on any particular
server/application combination. You can deploy the appropri-
ate total hardware complement to handle your peak aggregate
loads rather than deploy individual pieces of hardware for
every type of task. Doing so lets you keep your total hardware
installation busy and earning its keep, instead of sitting idly
by waiting for the next task that might suit a specific server/
application combination.
Create a Manageable
Upgrade Path
Upgrading software or operating systems can be a huge task.
Virtualization lets you split up the task and do it at a pace
slightly less insane than an all-nighter met in the morning by
end-user panic. In a virtualized workplace, you can upgrade
one group, spend some quality time getting to know them

and how they’re getting along with their upgraded systems,
and then use that knowledge to upgrade the next group on
your list.
Manage Outages (Expected and
Unexpected) Dynamically
For scheduled outages, a virtualized environment lets you
shift resources to cover where the outage will occur. And
with live migration tools, you can move virtual machines
(and the users accessing applications on them) dynamically
and transparently between systems. Your end-users need
never skip a beat. Instead of getting an e-mail before the
e-mail server goes down for routine maintenance, they
never get an e-mail at all.
Virtualization can also help enhance disaster recovery:
Should a VM fail for any reason, a new instance of a VM
can be started at a remote location almost immediately.
Nice, huh?

Notes

Virtualization for Dummies

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