optimized desktop infrastructure using dell flexible ......2009/02/21 · offer advantages for...
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Flexible Computing
DELL POWER SOLUTIONS | March 20091 Reprinted from Dell Power Solutions, March 2009. Copyright © 2009 Dell Inc. All rights reserved.
IT administrators face a variety of challenges
related to desktop management, including the
need to enhance management, mobility, and
security while efficiently carrying out asset tasks
such as procurement, provisioning, support, and
migration and patch management. Flexible comput-
ing technologies offer an alternative to traditional
desktops that help address some of these chal-
lenges. OS and application streaming, server-hosted
client virtual machines (VMs), and graphics redirec-
tion have evolved to provide value beyond the tra-
ditional presentation virtualization domains of the
Citrix Presentation Server™ and Citrix XenApp™
platforms.
The Dell Flexible Computing Solutions suite of
products and services is designed to centralize the
processing and storage resources of a distributed
computing environment. This suite provides an
architecture that can help increase control, manage-
ability, and security while helping reduce total cost
of ownership and enhancing desktop continuity.1
Each of these solutions can offer organizations tech-
niques for consolidating distributed desktop assets.
This article outlines the features and usage models
of the different solutions.
Dell Flexible Computing SolutionSThe Dell Flexible Computing Solutions suite is
composed of three main solutions: the Dell
On-Demand Desktop Streaming™ (ODDS) solution, the
Dell Virtual Remote Desktop (VRD) solution, and the
Dell Dedicated Remote Workstation (DRW) solution.
Organizations may also consider scenarios where one
or more Dell Flexible Computing Solutions are used
along with other complementary technologies to help
efficiently solve their end-user computing needs.
Dell on-Demand Desktop StreamingThe Dell ODDS solution utilizes Dell OptiPlex™ desk-
top clients with Dell EasyConnect™ technology, Dell
PowerEdge™ servers, and the Citrix Provisioning Server™
for Desktops platform (see Figure 1). In combination,
these components create a solution based on disk-
less desktop clients that receive a streamed OS
image from a streaming server in real time over a
100 Mbps Ethernet LAN. The desktop client uses its
local processor, memory, and graphics capabilities
to optimize the end-user experience.
ODDS works by having a factory-optimized
OptiPlex 755, OptiPlex 760, OptiPlex 960, or OptiPlex
FX160 client mount and boot its OS partition using a
The Dell™ Flexible Computing Solutions suite of products and services is designed to simplify and centralize administrator control over end-user desktops while help-ing enhance security and reduce total cost of ownership. Understanding the features and usage models of each solution can help administrators optimize their use in enterprise environments.
By John Schouten
Ramesh Radhakrishnan, Ph.D.
Optimized desktOp infrastructure using dell flexible cOmputing sOlutiOns
Related Categories:
Citrix Systems
Dell OptiPlex desktops
Dell Precision workstations
Flexible computing
Virtualization
VMware
Visit DELL.COM/PowerSolutions
for the complete category index.
1 For more information on the components and advantages of Dell Flexible Computing Solutions, see “Flexible Computing: Advancing End-User Productivity with Centralized Control,” by Jeremy Ford and Roberto Ayala, in Dell Power Solutions, November 2008, DELL.COM/Downloads/Global/Power/ps4q08-20090139-Flex.pdf.
2DELL.COM/PowerSolutionsReprinted from Dell Power Solutions, March 2009. Copyright © 2009 Dell Inc. All rights reserved.
virtual disk (vDisk) hosted on a streaming
server over an Ethernet network. During a
client’s first boot from the streaming server,
the client’s Media Access Control (MAC)
address is added to a database that pro-
vides granular control over device identity
and vDisk authorization. The OS streaming
server then intelligently streams its vDisk
to the client in real time, providing only the
necessary information to help optimize
client performance and network traffic.
Once configured, Citrix Provisioning
Server enables streaming vDisks from the
streaming servers to desktop clients in
one of two modes:
Private one-to-one mode:■■ Creates a
read/write vDisk for each downstream
client—essentially taking the hard drive
out of the client and storing it on the
server
Shared one-to-many mode:■■ Streams a
read-only vDisk to multiple clients
Depending on workload, typical ratios
for the one-to-many mode can range from
50 to 100 clients per vDisk. Because each
change to this vDisk affects many clients,
this model helps dramatically reduce the
number of touch points in the operational
management of system images, patching,
and OS updates.
Dell Virtual Remote DesktopThe Dell VRD solution utilizes Dell OptiPlex
FX160 thin clients, Dell servers and storage,
and Citrix® XenDesktop™ or VMware® View
virtualization software to run desktop oper-
ating systems and applications as VMs
hosted on x86-based servers (see Figure 2).
End users access their VMs from a client
device using either the Citrix Independent
Computing Architecture (ICA®) protocol in
the case of Citrix XenDesktop, or the
Microsoft® Remote Desktop Protocol (RDP)
in the case of VMware View. These proto-
cols provide a bitmap-cache-optimized
protocol designed to work well in low-
speed, wireless, and high-speed networks.
In this solution, an abstraction layer is
set down on the server in the form of a
hypervisor. This abstraction layer provides
a method to create numerous logical par-
titions within the server, each of which is
populated with a VM running the Microsoft
Windows® XP or Windows Vista® OS. The
VMs run concurrently on this abstraction
layer, providing a co-shared desktop VM
environment running on highly available
server and storage hardware.
This architecture is designed to con-
tain, secure, and centralize the manage-
ment of desktop VMs and their associated
applications regardless of the access
device or user location. Like server virtu-
alization, this solution can offer advan-
tages related to the simplification of
desktop provisioning, administration, and
management tasks. In addition, this solu-
tion enhances data security and continuity
through the centralization and contain-
ment of the OS image and data
structures.
Dell Dedicated Remote WorkstationThe Dell DRW solution is based on a dedi-
cated Dell Precision™ R5400 rack worksta-
tion located in a centralized data center
and allocated on a per-session basis (see
Figure 3). This one-to-one mapping of
workstation to user session provides the
advantage of dedicated processor, memory,
and graphics capabilities. This approach
Diskless DellOptiPlex client
Flexibleapplications
Microsoft Windows XPor Windows Vista vDisk
Dell PowerEdgestreaming servers
Local processing
Many to one
Figure 1. Dell On-Demand Desktop Streaming architecture
Figure 3. Dell Dedicated Remote Workstation architecture
Figure 2. Dell Virtual Remote Desktop architecture
Client device
Virtualdesktop
Virtualization layerRemote processing
Virtualdesktop
MicrosoftWindows XP
MicrosoftWindows Vista
Dell PowerEdge serverOne to many
Client device
Remote processing
Virtualdesktop
Microsoft Windows XPor Windows Vista
Dell Precision R5400rack workstationOne to one
Flexible Computing
DELL POWER SOLUTIONS | March 20093 Reprinted from Dell Power Solutions, March 2009. Copyright © 2009 Dell Inc. All rights reserved.
helps ensure a performance-oriented envi-
ronment and avoids virtualization overhead
or resource-sharing complexities.
A dedicated hardware compression/
decompression device resides within the
rackable workstation and redirects high-
performance graphics to a complemen-
tary peer device through hardware-assisted
Teradici PC-over-IP technology. The peer
device provides decompression of the
PC-over-IP stream and enables applica-
tions to execute remotely on the worksta-
tion. The dedicated remote workstation is
configured in a one-to-one fashion, acting
as a dedicated device per user session. If
more than one user is configured for
access per device, then the Microsoft
Windows profile architecture preserves
user settings. Profile optimizations can be
applied using folder redirection and Group
Policy objects (GPOs) for streamlining the
user session environment.
Complementary technologiesOrganizations may also choose comple-
mentary technologies such as application
streaming or client-hosted virtualization
within a Dell Flexible Computing Solution
to further enhance the manageability and
utility of a centralized enterprise client
infrastructure.
In the application streaming model,
applications are streamed on demand from
a centralized server to the target client OS.
This target OS may reside within either a
server-hosted VM or on a traditional local
or mobile desktop device. Administrators
package, provision, and manage applica-
tions centrally, which helps improve man-
agement and access control compared
with a traditional desktop environment. In
the case of a local desktop, streamed appli-
cations execute processes and threads
locally, providing end users with a tradi-
tional client experience. Devices can func-
tion in either an online (cached) mode or
an offline mode.
In the client-hosted virtualization
model, a virtualization layer is applied to
the desktop client. Target VMs reside and
operate within the context of this one
client system. Because the application
suite is contained within a predetermined
local VM, administrators have the flexibility
of deploying enterprise desktop VMs on a
multitude of enterprise desktop assets
while enhancing the security attributes
around both the client’s VM execution and
data environment. This helps increase the
protection of enterprise assets and may
also allow the use of nonconforming hard-
ware assets. From a systems management
perspective, this model does incur some
additional burden, as each VM and its local
host OS become a target for management,
patching, and updating.
CompaRiSon oF Flexible Computing appRoaCheSFigure 4 highlights key features of ODDS
using Citrix Provisioning Server for Desktops,
VRD using Citrix XenDesktop or VMware
View, and DRW using Teradici PC-over-IP,
along with the complementary application
streaming and client-hosted virtualization
technologies. Each of these approaches can
offer advantages for enterprise desktop
centralization and optimization and support
a myriad of client workloads, usage models,
and client devices.
For example, the diskless client archi-
tecture of ODDS using Citrix Provisioning
Server for Desktops is well suited for orga-
nizations with large groups of users utiliz-
ing the same desktop image (OS and
applications). It is designed to provide
excellent application isolation while
offering uncompromised processing and
graphics performance. For administrators,
its advantages can include user session
mobility, rapid deployment and provision-
ing, and enhanced data security through
centralized data storage. ODDS can also
provide excellent support for peripherals
when CD/DVD, audio, and parallel or serial
port access are required.
A natural extension for ODDS is to
service a VRD environment. This hybrid
approach reflects the Citrix XenDesktop
architecture, in which the hypervisor resides
on the x86-based server hardware while
the OS streaming through ODDS provides
the one-to-many OS imaging infrastructure.
Each vDisk is assigned to a group of VMs
and helps ease storage and management
requirements. Rapidly deploying VMs using
this technique enables the optimization of
both server and storage hardware. The
Citrix Desktop Delivery Controller manages
the incoming requests for VM access and
automates the deployment and connection
state of the desktop VMs.
VRD using VMware View utilizes
VMware View Connection Manager. This
connection manager interfaces directly with
VMware ESX through the VMware vCenter
Server (formerly VMware VirtualCenter)
console and VMware ESX application pro-
gramming interface (API). This vCenter
Server integration provides a centralized
console to manage client access, VM map-
pings, and the automation and orchestra-
tion of the virtual desktop environment.
Storage optimizations are accomplished
through VMware Virtual Machine File
System (VMFS) using its snapshot and clon-
ing capabilities. These VMFS operations can
provide advantages for both production
and development systems where writable
snapshots can be used to create one-to-
many imaging architectures.
Like traditional server virtualization plat-
forms, Citrix XenDesktop and VMware View
use a hypervisor to host remote desktop
VMs. This hypervisor provides an abstrac-
tion layer that enables server hardware
independence and portability within the
data center environment. While at the end-
point device, ICA or RDP provide geograph-
ical independence between the endpoint
and the server-hosted VM. This combination
of hardware independence at the server
and geographical independence using ICA
or RDP at the endpoint device enables a
flexible and agile framework for desktop
deployment—one that can offer advan-
tages such as remote access, increased life
cycles for endpoint devices, session porta-
bility, and mobility. Administrators should
carefully consider the usability character-
istics of this solution in environments where
high-performance graphics and peripheral
access are required.
4DELL.COM/PowerSolutionsReprinted from Dell Power Solutions, March 2009. Copyright © 2009 Dell Inc. All rights reserved.
on-Demand Desktop Streaming
using Citrix provisioning Server
for Desktops
Virtual Remote Desktop using
Citrix xenDesktop or Vmware View
Dedicated Remote Workstation
using teradici pC-over-ip
application streaming
Client-hosted virtualization
Device independence ■ ■ ■
Session mobility ■
(may require roaming profiles)
■ ■
(may require roaming profiles)
■ ■
Wireless capability ■
Rapid provisioning ■ ■ ■ ■
Remote access ■ (ICA or RDP over Secure
Sockets Layer [SSL])
Centralized storage ■ ■ ■ ■ ■
Offline support for mobile clients
■ (with future offline support planned in
VMware View)
■ ■
Automated provisioning
■ (with Citrix Desktop
Delivery Controller or VMware View Manager)
■ (with Microsoft
Installer [MSI] packages or GPOs)
■ (with Microsoft
Enterprise Desktop Virtualization)
Enhanced data security
■ ■ ■ ■
Management tools Citrix Provisioning Server console
Citrix XenCenter™ or VMware vCenter
Server console
Teradici PC-over-IP Management Console and connection broker
Profiling tools and Microsoft
Active Directory® directory service
Existing client management tools such
as Microsoft Active Directory–enabled
GPOs, MSI packages, and Systems
Management Server
Guest OS support Microsoft Windows XP and Microsoft Windows Vista operating systems
Microsoft Windows XP and Microsoft Windows Vista operating systems
Microsoft Windows XP, Microsoft Windows
Vista, and Linux® operating systems
Microsoft Windows XP and Microsoft Windows Vista operating systems
Microsoft Windows XP, Microsoft Windows Vista,
Microsoft Windows Server®, and Solaris operating systems
Licensing Microsoft Windows Vista Enterprise
Centralized Desktop (VECD) and Software
Assurance (SA) licenses
VECD and SA licenses Microsoft Windows XP original equipment manufacturer (OEM)
license
VECD, SA, and Microsoft Desktop Optimization Pack (MDOP) licenses
Local OS license and VM OS license
Server-to-client ratio One to many One to one (persistent) or one to many (nonper-
sistent)
One to one One to many One to one
Core technology User Datagram Protocol (UDP) and vDisks
RDP, connection broker, and hypervisor
Teradici PC-over-IP Microsoft AppV™ or VMware ThinApp soft-
ware
Microsoft Virtual PC, VMware ACE, VMware
Workstation, or VMware Player
Example use case Local device or virtual remote desktop
Remote access using ICA or RDP over SSL for structured-task
and general-purpose productivity software
High-performance or precision workloads
and applications where visual interpretation is
important
Local device, mobile device, or VM
Local device, mobile device, or nonconforming
hardware assets
Figure 4. Comparison of Dell Flexible Computing Solutions and complementary technologies
Flexible Computing
DELL POWER SOLUTIONS | March 20095 Reprinted from Dell Power Solutions, March 2009. Copyright © 2009 Dell Inc. All rights reserved.
DRW with hardware-assisted Teradici
PC-over-IP technology is designed to pro-
vide a flexible, centralized deployment
model while still providing the processor,
memory, and graphics performance of a
high-performance workstation. The Dell
Precision R5400 workstation features an
industry-standard dual-socket design
using quad-core processors and large
memory capacity to deliver a powerful 3D
OpenGL graphics experience and support
for up to four monitors using a PCI x16
graphics card for remote users. Functional
benefits of the DRW model can include
support for increased distances to inhos-
pitable or hazardous areas. Administrative
benefits can include security enhance-
ments through device centralization and
the simplification of adds, moves, and
changes as IT resources and project teams
are reassigned or reallocated.
Organizations might consider a multi-
tiered approach when considering flexible
computing. For example, a foundational
technology like VRD may be used along
with application streaming and OS stream-
ing (see Figure 5). In this example, a virtual
desktop is rapidly provisioned and assem-
bled for the user. The foundation technol-
ogy is VRD while the application and image
management system are optimized using
application and OS streaming. The final
desktop reflects a composite view of the
three virtualization technologies. By com-
bining a variety of approaches, organiza-
tions can optimize their environment to
help meet the needs of both IT administra-
tors and end users.
Dell optiplex Fx160 enDpoint DeViCeIn flexible computing architectures, the
endpoint device acts as the interface
between the client task and the compute
infrastructure. While a myriad of devices
exist, and in some cases organizations
may utilize existing assets as endpoint
devices, it is important to understand the
usefulness of the Dell OptiPlex FX160 end-
point device.
The OptiPlex FX160 can work with a
variety of solution concepts. Its founda-
tional approach is to enable flexible com-
puting, and as such this device can be
configured for either an ODDS environ-
ment using Citrix Provisioning Server or a
VRD environment using either Citrix
XenDesktop or VMware View.
Flexible DeSktop inFRaStRuCtuReA centralized enterprise client infrastruc-
ture model helps provide a data and
application containment strategy while
helping ensure flexible access for end-
point devices and end users. Along with
the functional benefits of centralization
and the agility that virtualization can pro-
vide, these solutions can help organiza-
tions achieve a return on investment in
multiple dimensions, including the econo-
mies of provisioning, image management,
and reductions in both user-side visits
and adds, moves, and changes for the
endpoint devices. Together, ODDS with
Citrix Provisioning Server for Desktops,
VRD with Citrix XenDesktop or VMware
View, and DRW with Teradici PC-over-IP
offer a holistic approach to flexible
computing that can help meet a variety
of needs.
John Schouten is an enterprise strategist
with Dell. His position draws on his exper-
tise in enterprise infrastructure related to
servers and storage. For the past 15 years
he has focused primarily on infrastructure
solutions related to Microsoft Windows,
Citrix, VMware, and high-availability clus-
tering. He holds Microsoft Certified
Systems Engineer (MCSE), Citrix Certified
Enterprise Administrator (CCEA), and
VMware Certified Professional (VCP)
certifications.
Ramesh Radhakrishnan, Ph.D., is a
member of the Scalable Systems Group
at Dell. His interests include performance
analysis and characterization of
enterprise-level benchmarks. Ramesh has
a Ph.D. in Computer Engineering from the
University of Texas at Austin.
QuiCk link
Dell Flexible Computing Solutions:DELL.COM/FCS
Figure 5. Example three-tiered flexible computing environment
Applications
Dyn
amic
ass
embl
y
Applicationstreaming
Application 1 Application 2 Application n Applicationprovisioning
Profile Roaming profileor folder
redirection
User profilemanagement
Image OSstreaming
Imageprovisioning
HKEY_CURRENT_USER
Sales Human resources Marketing
Target devices
VMVM VM