Guidelines for Migration to
Server-based Computing / VDI
and Thin Clients: Analysis and
Implementation
Centralized IT infrastructures with standardized, efficient desktops will lower the TCO and ­considerably
improve internal processes, yielding smoother workflows. These guidelines cover the most important considerations and migration steps for the backend and frontend of an IT sysem.
Table of Contents
1. Introduction: Why are centralized IT models so successful?
3
2. What centralized IT models are available?
3
3. Selecting the desktops - new hardware or repurposing old PCs
4
4. Thin clients as desktop workstations – what requirements have to be met?
4
5. TCO: How high are the overall cost savings?
5
6. The best time to migrate
7
6.1 Desktop life-cycles
7
6.2 Change management – simplified by centralized IT
7
7. Preparing for and carrying out the migration
8
7.1 Step 1: Analysis of existing configuration and planned configuration
8
7.2 Step 2: Evaluation phase 8
7.3 Step 3: Dimensioning the servers
9
7.4 Step 4: Test phase and pilot phase
9
7.5 Step 5: Final roll-out
10
8. Ensuring a clean migration; avoiding errors
10
2/11
Reasons for centralized IT models:
• Decreased desktop administration workload
• Decreased overall IT costs
• Increased security
1. Introduction: Why are centralized IT models so
successful?
For some years now, the manner in which both private and public organizations provision their IT applications has been steadily undergoing a
major paradigm change. Companies and government agencies are
replacing their client/server networks based on PCs (fat clients) with cen-
• Achieving compliance with legal
rules and regulations
• Increased availability of applications
• Increased flexibility of the IT infrastructure (faster/
cheaper roll-outs of workstations, easy scalability)
• Lower environmental impact (less energy consumption,
CO2 emissions and e-Waste)
tralized infrastructures featuring thin clients. The reason for this move? By
doing so, they can save up to 70% in the total cost of ownership (TCO)
of their systems. Additional arguments in favor of such a migration are
Box 1
greater data security, higher system availability and improved safeguarding of business continuity (see Fig.1). Yet during planning the following key
standard applications, the model known as server-based computing (SBC)
questions need to be carefully analyzed and answered: Which solution for
should be the first choice due to its inherent efficiency. The most impor
centralizing IT and standardizing the desktop environment is the right one
tant
for the given case? When is the best time to proceed with the migration?
merly known as Presentation Server™ and now part of XenDesktop™)
What steps should be followed in implementing the changeover?
and Microsoft® with Remote Desktop Services (formerly known as Ter-
SBC
solution
providers
are
Citrix®
with
XenApp™
(for
minal Services), which is a component of Microsoft® Windows Server™
2. What centralized IT models are
available?
2008 R2.
The first step is to analyze what types of centralized provision of IT should
For mixed application environments that cannot be consolidated or IT
be considered and, of these, which ones might possibly be correct for
environments with a large number of power users or knowledge work-
the company concerned. For instance, are there IBM mainframe applica-
ers needing high performance, a virtual desktop infrastructure (VDI) is the
tions or legacy host systems that need to be integrated into the new envi-
recommended solution. The most important VDI solutions available are
ronment? Furthermore, are other company departments and/or affiliated
the following: VMware View™, Citrix XenDesktop™ and the Microsoft® VDI
companies already using centralized IT environments? How many users
Suite. In contrast to SBC, in a VDI environment individual application that
need what kind of applications? In the case of an IT environment with many
several users can access at once (shared applications) are not separately
Server Worlds and Communication Protocols and their Associated Clients on the Thin Client
Windows
Server
Citrix
Environment
RDP/RDS
ICA
RDP/RDS
Client
ICA Client
Citrix Receiver
Linux/
Unix
Server
X11R6
XDMCP
X11R6
XDMCP
Legacy
Host Mainframe
Web
Applications,
Portals
diverse
TCP/IP
RDP/RDS/ICA/
PCoIP
Web browser,
Java, .NET
View/ICA/
RDP/RDS Client /
PCoIP
Host
Emulation
Virtual
Desktops
Local Protocol Clients on the Thin Client
Fig.1: Universal access to a great variety of centralized IT infrastructures
3/11
Server-based Computing (SBC)
User
thin
client
User
thin
client
ICA
ICA
Virtual Desktop Infrastructure (VDI)
User
thin
client
User
thin
client
User
thin client
User
thin
client
ICA
Virtual
desktop
Terminal-server-capable
multi-user applications
Virtual
desktop
Virtual
desktop
=
=
=
Applications
Applications
Applications
+
+
+
Operating
system
Operating
system
Operating
system
Citrix XenApp
Server OS (MS Server 2008 R2)
Hypervisor (Microsoft Hyper V,
Citrix XenServer, VMware ESX, …)
Server hardware
Server hardware
Fig. 2: SBC model vs. VDI model
provisioned. Instead, with VDI each user has his own virtual desktop with
accomplished by transferring the thin client software to the end devices
his own specific operating systems and application environment hosted in
by means of a USB token or a CD-ROM (supplied with the UDC) or else
the data center (Fig.2). Depending on the method employed by the solu-
by means of Microsoft® Windows® Server 2003 RIS. Once this step is
tion provider, these virtual desktops can either be provided as needed or
completed, these end devices can be remotely managed and updated by
dynamically assembled; that is, provisioned or compiled. Furthermore, as
means of the IGEL Universal Management Suite (UMS), just like any other
a part of cloud computing services, server resources (capacities), virtual
IGEL thin client.
hosted desktops (VHD) or applications (Software as a Service or "SaaS")
can be outsourced as needed from external providers.
3. Selecting the desktops new hardware or repurposing old PCs
4. Thin clients as desktop workstations – what
requirements have to be met?
A critical argument in favor of centralized and external provisioning models
is the fact that the user needs only a cost efficient thin client to be able
Depending on the goals of the project, the desktop migration can be either
to access either the centrally or externally provided IT resources. These
completed by installing new thin client hardware or by using the exist-
approaches also include the opportunity to standardize the desktop envi-
ing end-user devices (PCs, nettops, thin clients and notebooks). In the
ronment and to minimize the TCO, and not just on the server side. However,
second case, the basis for the migration process is thin client software
these approaches also mean that the thin client software (firmware) must
that makes the end devices remotely manageable and prevents data from
have all the necessary protocols and software clients (Fig. 1). Specifically,
being saved locally on the converted fat clients.
this means that Microsoft-based environments require the Remote Desktop Protocol (RDP). Similarly, Citrix solutions require the software client
However, what speaks in favor of a new investment in thin client hardware
Citrix® ICA. With VMware View™ the best performance can be achieved
is, above all, their long service life of from six to eight years as well as
by using PCoverIP (PCoIP); however, this solution will require considerably
the major energy savings to be realized. In contrast, existing end devices
more server resources than standard SBC. In larger VDI environments,
that are, for an interim transitional period, converted to run with a mod-
thin clients should also support the respective connection broker that
ern thin client operating system usually can continue to be used for two
assigns the correct virtual desktops to the respective end devices. Thin
to three more years. The advantages of this interim, relatively temporarily
clients can also access host and mainframe applications if their firmware
period includes the fact that investments in existing equipment can be
also offers a collection of compatible terminal emulations. Furthermore, if
leveraged and safeguarded and that the costs of the desktop migration
a local web browser is included, then thin clients can use TCP/IP (Trans-
can be extended over a longer period of time – improving liquidity. Exist-
mission Control Protocol / Internet Protocol) to access directly hosted web
ing end devices can be converted using the Universal Desktop Converter
applications, portals and other cloud computing services.
(UDC) from the German thin client manufacturer IGEL Technology. This is
4/11
PC vs. Thin Client (Example Calculation for 130 Clients)
5. TCO: How high are the overall cost
savings?
2.500 €
The greatest potential for savings is provided by conventional server-based computing. For example, the renowned Fraunhofer Insti-
73 €
2.000 €
745 €
tute for Environmental, Safety and Energy Technology (UMSICHT)
(Oberhausen, Germany) has conducted a study that reveals that a
Citrix -based environment with IGEL thin clients offers overall savings
®
1.500 €
Decommissioning
Operation
Startup
1.000 €
(TCO) of 70% compared to an unmanaged PC environment (Fig. 4).
While in its study, Fraunhofer UMSICHT considers an SBC/thin client
51 €
369 €
1.358 €
953 €
500 €
based IT infrastructure to be worthwhile starting with ten workstations, another German study conducted by an IT software/systems
supplier and developer showed that such a changeover will pay-off
starting with only 7 workstations. (Source: R. Wallis UBA EDV GmbH,
Ibbenbüren, Germany 2006). In addition, a somewhat less detailed
study by Gartner estimated the typical savings to be up to 50%. In
H A R D WA R E + S O F T WA R E
Costs for a client/server (C/S) structure with 100 PCs in
Euros
Purchasing 100 business PCs
50,000
0€
PC
Thin Client
Fig. 4: IT costs for a desktop infrastructure for a typical organization
with 150 to 300 employees, Source: Fraunhofer Institute for Environmental, Safety and Energy Technology (UMSICHT) / IGEL Technology: Thin Clients 2011 – Ecological and economical aspects of
virtual desktops
Server-based computing (SBC) with 100 thin clients and 3
Citrix XenApp servers in Euros
Purchasing the server hardware 3 Citrix XenApp
servers
Air conditioning system for cooling the
servers, uninterruptible power supply (UPS)
100 operating-system licenses (OEM)
Microsoft® Windows® 7 Professional
12,500
15,000
5,000
3 server licenses for Microsoft Windows Server 2008
1,800
100 TS-CAL licenses (HEK)
8,500
100 Citrix user licenses
6,000
100 IGEL thin clients
20,000
TCO
O P E R AT I O N
R O L L- O U T
(The file server and network hardware are not reflected in this calculation since they are the same in both system configurations.)
Total Investment Costs:
62,500
Work time for PCs including selection, evaluation,
testing, removal/installation, disposal and setup (4
hours per PC)
30,000
Total Costs for Roll-out:
30,000
Administration, maintenance and support
(8 hours/PC)
60,000
56,300
Work time for thin clients including selection, evaluation, testing, removal/installation, disposal and setup
(0.5 hours per TC)
3,750
Work time for setting up the servers and centralizing
applications (100 hours)
7.500
11,250
Administration, maintenance and support
(30 hours/server)
6,750
Administration, maintenance and support for
thin clients (0.5 hour/TC)
3,750
Hardware costs (50 Euros/PC)
5,000
Hardware costs (100 Euros/Citrix server)
300
Power costs for 100 PCs (average
operating time: 8 hours x 220 days)
4,131
Power costs for 100 thin clients including share of
power requirements for server hardware and cooling; operating time: 9 hours x 300 days)
826
Total Operating Costs (per year):
69,131
11,626
TCO after 1 year:
161,631
( = HW+SW + roll-out + 1 year of operation)
79,176
TCO after 2 years:
230,762
( = HW+SW + roll-out + 2 years of operation)
90,802
TCO after 3 years:
299,893
( = HW+SW + roll-out + 3 years of operation)
102,429
TCO after 5 years:
438,155
( = HW+SW + roll-out + 5 years of operation)
125,681
TCO Savings After 5 Years: 312,474
Return on Investment (ROI): 71%
Table 1: TCO Comparison: PC environment and SBC (Citrix XenApp™) environment with thin clients
5/11
H A R D WA R E + S O F T WA R E
Costs for a client/server (C/S) structure with 100 PCs in
Euros
Purchasing 100 business PCs
50,000
Costs for VDI with 100 virtual desktops (Citrix XenDesktop) and 100 thin clients in Euros
Purchasing the server hardware
6 Citrix XenApp servers
30,000
Air conditioning system for cooling the
servers, uninterruptible power supply (UPS)
10,000
Server licenses (bare-metal hypervisor)
100 operating-system licenses
Windows 7 Professional (OEM)
12,500
None
100 operating-system licenses Windows 7
Professional (OEM)
12,500
100 IGEL thin clients
20,000
R O L L- O U T
(The file server and network hardware are not reflected in this calculation since they are the same in both system configurations.)
Total Investment Costs:
62,500
Work time for PCs including selection, evaluation,
testing, removal/installation, disposal and setup
(4 hours per PC)
30,000
72,500
Work time for servers including selection, evaluation, testing, removal/installation, disposal and
setup (5 hours per server)
2,250
Work time for virtual desktops, including testing
(2 hours/virtual desktop)
15,000
O P E R AT I O N
Work time for thin clients including selection, evaluation, testing, removal/installation, disposal and
setup (0.5 hours per TC)
Total Costs for Roll-out:
30,000
Administration, maintenance and support
(8 hours/PC)
60,000
21,000
Administration, maintenance and support for virtual
desktops (4 hours/virtual desktop)
30,000
Administration, maintenance and support for
thin clients (0.5 hour/TC)
3,750
Administration and maintenance per server
(10 hours each)
4,500
Hardware costs (50 Euros/PC)
5,000
Hardware costs (100 Euros/Citrix server)
600
Power costs for 100 PCs (average operating time:
9 hours x 300 days)
4,131
Power costs for thin clients (average operating
time: 9 hours/day x 300 days)
551
Power costs for VDI servers (6 x 250 W average consumption; operating time: 24 hours/day x
365 days)
100 Citrix XenDesktop licenses at 76 Euros each
100 Microsoft VDA licenses at 100 Euros each
Total Operating Costs (per year):
TCO after 1 year
TCO
3.750
69,131
161,631
2,234
7,600
10,000
59,235
( = HW+SW + roll-out + 1 year of operation)
152,735
TCO after 2 years
230,762
( = HW+SW + roll-out + 2 years of operation)
211,969
TCO after 3 years
299,893
( = HW+SW + roll-out + 3 years of operation)
271,204
TCO after 5 years
438,155
( = HW+SW + roll-out + 5 years of operation)
389,673
TCO Savings After 5 Years: 48,482
Return on Investment (ROI): 11%
Additional calculation factors:
Hourly rate for IT service in Euros/hour: 75; average share of effective power for PCs: 90 W; energy costs in Euros/kWh 0.17; average share of effective power for
TCs: 12 W
Table 2: TCO Comparison: PC environment and VDI (Citrix XenApp™) environment with thin clients
6/11
fact, for VDI environments Gartner determined a savings potential of
PCs every three to four years. Thin clients, whose firmware can be
2 to 10%. In this case, the primary reasons given for this lower figure
updated with new protocols, software tools and clients, allowing
lie in the higher costs for server hardware, licenses and management
service life cycles of from six to eight years to be achieved, are a
of the virtual desktops. The calculations of the TCO savings for SBC
welcome alternative to the usual repeated reinvestments in expen-
and VDI for an operating period of five years are shown in Tables 1
sive PC hardware. Attempts to extend the usual PC life cycle will
and 2 below.
also prove to be expensive since PCs that have been in service
for more than four years require a disproportionate amount of ser-
An Example of User Success:
The Hong Kong branch office of the German fashion
supplier Heiss has strengthened its leading competitive
position with SBC and IGEL thin clients. The reasons for
Heiss’ strategic replacement of desktop PCs with thin clients were quite obvious: “Our old system was very failureprone,” recalls Rani Li, Accountant & Administration Officer at Heiss. “For instance, while synchronizing our sales
and inventory data with the company headquarters, we
vice and maintenance, which compounds their operational costs.
In fact, it's often the case that these very end-user devices have
been upgraded many times already and are now reaching the limits of their capacity for improvement. For instance, it is highly likely
that the existing hardware will not support any more RAM, a larger
hard disk or a larger compact flash memory, or furthermore, that
the CPU itself is too weak to handle such upgrades. In this case,
too, desktop standardization by means of thin clients is a presents
itself as truly viable solution for permanently cutting ongoing costs.
frequently lost data – a situation that had a considerable
negative impact on day-to-day business. In fact, some of
our personnel used to have to spend hours manually correcting the data. Once, one of our branches even ended
up having to record a loss because the inventory figures
were incorrect.”
Box 2
Overview of suitable migration times:
Desktop side:
• Increased PC failure rates
• Too much time, effort and expense for desktop
maintenance and administration
• Deployment of new desktop operating systems
• Completed amortization of PC hardware
6. The best time to migrate
• New PCs needed at the end of previous PC life cycle
Centralizing IT services and standardizing its associated desktop
Computer-center side:
environment requires a certain level of planning and organization
• New equipment needed in computer center
to properly prepare for the implementation phase. However, there
• Conversion to virtualized servers
are certain situations in which the time and effort spent in prepa-
• Energy optimization of computer center
ration will be less. For instance, this is the case when there are
External
upcoming changes already schedulded for the data center itself.
• Company mergers
The most frequent reasons for performing a system migration are
• Company expansion
the desire to improve IT availability and safeguard business continuity. As part of a pending modernization program for the physical
Box 3
data center infrastructure, the system is redesigned with a more
powerful, more available and more efficient backend. Modern, effi-
6.2 Change management – simplified by centralized IT
cient, scalable and redundantly set up server, storage and network
Changes in organizational structures and requirements can also
components, a scalable cooling system and an uninterruptible
present a favorable opportunity for a migration, especially mergers
power supply (UPS) system are the best prerequisites for success-
and takeovers. With centralized IT infrastructures and a standard-
fully implementing SBC and VDI. Another incentive for a migration
ized desktop environment, the data from two enterprises can be
is the (pending) final amortization or the end of the service life of
consolidated considerably more quickly and easily, and the desk-
the server hardware and other data center components, especially
top environment can be more readily adapted to meet the new
when the majority of the IT equipment has become outdated.
scenarios and conditions. Over the mid/long-terms, the new consolidated company will not only benefit from a lower TCO but also
6.1 Desktop life cycles
from greater IT scalability. These revisions will not only improve
In order to be able to use the latest operating systems and the new-
competitiveness but also the initial financial basis for facilitating
est programs and functions, companies and government agen-
further growth and acquisitions. What's more, it will be faster and
cies used to have to acquire new and considerably more powerful
easier to set up and open new branch offices. This is because roll7/11
ing out a thin client can be readily accomplished in a few minutes,
The most important decision criterion is the application environ-
while installing a PC can take several hours.
ment. Standard applications can be most efficiently provisioned by
The migration to SBC or VDI with thin clients is not only an ideal
means of SBC. For those applications that are processing-intensive
way to bring about long-term, sustained reductions in IT costs,
or graphics-intensive as well as test stations for software develop-
it also offers the perfect opportunity to readily optimize mission-
ers, VDI is the better way to go. Web-based applications can be
critical enterprise processes. The typical goals to be achieved in
very efficiently provisioned by means of thin clients with an inte-
the course of what is known as "business process reengineering"
grated browser (included in the firmware), a method that bypasses
include improved data consistency, data transparency and pro-
the central server in the data center, thus conserving resources.
cess integrity.
7. Preparing for and carrying out the
migration
The process of migrating to an SBC or VDI environment with thin
clients can be subdivided into five major project phases:
• Step 1: Analysis of the existing configuration and
Questions to ask about the initial situation
(analysis of existing configuration):
• What kind of user environment is currently being used?
• How high is the share of standard applications such as
MS-Office applications, Internet, e-mail, etc.?
• How many workstations use special applications or require
higher-than-average performance, such as for graphics
editing, CAD use or software development?
planned configuration
• Step 2: Evaluation phase
• Step 3: Dimensioning the servers
• What bandwidths are available in the LAN and WAN
(branch offices) systems?
• Step 4: Test phase and pilot phase
• Step 5: Final roll-out
• How many users have to work at the same time?
7.1 Step 1: Analysis of the existing configuration and
• What type of desktop infrastructure do I have in place?
planned configuration
• How high are the costs for my data center and
desktops?
The initial considerations concerning the migration begin with a thorough, fundamental analysis of the current situation and the desired,
final situation. In this respect, the critical questions and issues can
Box 4
be summarized as described in the f­ollowing overview: The desired,
final situation can be described based on analysis of the goals to be
Among other things, VDI is more cost intensive than SBC because
achieved (necessary end results). This analysis takes into account the
VDI licenses have to be renewed each year and each thin client
method of application provision (SBC, mainframe, VDI, web services,
must have its own, separate Microsoft Virtual Access License
etc.) and the desktop strategy (the desired level of thin client coverage).
(VDA). In contrast, with SBC the license fees are due only once –
In addition, this analysis can also include other goals such as soft-
per server and per user (e.g. for a TS-CAL and a Citrix user license).
ware and server consolidation, new system availability requirements,
The best way to determine the best solution for a given company
data security/backup, etc. The requirements of the new IT infrastruc-
is to conduct both initial lab and field testing. If, during the evalua-
ture are gathered and compiled along with all the prerequisites for the
tion phase, new requirements are identified, then the planners need
new, upgraded installation. The issues among them that are actually
to go back to the first step in the migration workflow and adapt
economically viable can be determined by means of a cost/benefit
the prerequisites for the new, upgraded installation (requirements
analysis. For instance, it may, in fact, be more economical to continue
specification).
operating certain special applications that are only used at individual
workstations locally on a PC instead of investing in the cost and effort
Evaluate thin clients in parallel with the software
of acquiring the expertise, hardware and licenses to include them in an
During the testing phase, the thin clients should be evaluated along-
additional VDI environment.
side the software because a well-chosen desktop solution can significantly improve overall performance and even compensate for a
7.2 Step 2: Evaluation phase
lack of server resources or bandwidth. A good example is provided
The most commonly used software solutions for centralized provision-
by the manufacturer IGEL Technology, whose Universal Desktop
ing of applications and/or desktops are Microsoft Windows Server™,
(UD) thin clients can relieve the workload on the centralized IT infra-
Citrix XenDesktop™ (including XenApp™) and VMware View™. When
structure through their own computing performance and local soft-
investigating software solutions, the following criteria should be evalu-
ware tools including a web browser, a multimedia player, a Thin-
ated:
Print client or an SIP client for IP telephony. Their direct access to
®
8/11
legacy host systems by means of integrated terminal emulation also
7.4 Step 4: Test phase and pilot phase
makes it unnecessary to run expensive middleware on the server.
The first tests of the overall proposed solution, including the serv-
This is a notable benefit because the use of middleware degrades
er hardware, the provisioning software, the thin clients and the
the performance of the overall system.
peripheral devices are followed by a pilot project for deploying the
first new IT workstations. This first, pilot-project roll-out involves all
7.3 Step 3: Dimensioning the servers
those user groups for which a typical user scenario was defined
The servers in the new IT environment should be dimensioned so
back during the first planning step. As a rule, these users will come
that in the event of the failure of an application server the remain-
not only from company departments but also from different com-
ing systems can readily take on the sudden, added workload. In
pany branch offices covering the entire range of possible applica-
addition, the hardware must be replaceable to the point that in the
tions to be encountered in the enterprise. The first thing to do in
event of a failure any portion can be quickly replaced by another
advance of the first roll-out is to create the relevant user groups
unit. These fundamental requirements can be very easily met by
and profiles on the servers. After this, all files locally stored on the
using server virtualization. The exact specifications of the server
PCs and the settings for the PCs themselves should be backed up
hardware depends greatly on the system requirements of the pre-
and transferred to the server. There are different migration tools
ferred software solution, on the number of users, their application
environments and the performance specifications of the thin clients
themselves. For SBC, the following general "rule of thumb" applies:
for Microsoft® Windows® Server 2008 R2 (64 Bit), each server can
support up to 200 standard (non-power) users. By contrast, in VDI
environments 25 standard users per server is a realistic load. In
addition to the user/server ratio, the user/client ratio also needs to
be determined. It should be kept in mind that not every employee
needs his own thin client, which means that the number of users
per server can most likely be somewhat reduced.
Important selection criteria for server
software:
• How high are the licensing costs (for servers, users and
clients)?
• How high are the system and resource requirements?
• What types of management capabilities and tools does the
solution offer?
• What security features are available?
• How well does the proposed solution balance loads?
• How high-performance/efficient is the solution when it
Important selection criteria for thin clients:
comes to supporting multimedia, printing and peripheral
• Is there a universal approach for as many user scenarios as
devices?
possible?
• What about the features of the management solution: no
licensing costs, profile-based, platform-independent and
easy and intuitive to operate?
• Future readiness: updateable firmware, enough RAM and
flash memory for updates
• Technological openness/flexibility: software clients, tools
and protocols for direct access to SBC, VDI, cloud services,
mainframes, VoIP, etc.
• Support for peripherals: USB, serial, parallel, PS/2, DVI (dual
or multiview capability)
• Network: LAN, WLAN, WAN, DSL, ISDN, etc.
• Security features: VPN client, smartcard support, etc.
Box 5
Box 6
available to facilitate this step. It's recommended that the personnel participating in the pilot project be part of a hierarchical structure so that the new technology becomes readily accepted at all
levels, from top to bottom, within the enterprise. During the pilot
project, the feedback from the initial set of users is collected along
with the technical results. If, as result of this dual information, new
requirements become evident, these should be critically evaluated
for inclusion in the final roll-out. In this case, the evaluation step
(Step 2) should then be repeated reflecting any changed conditions.
7.5 Step 5: Final roll-out
Once the pilot project (initial roll-out) has been successfully com-
Furthermore, what also needs to be determined is the desired level
pleted, the final roll-out for the SBC or VDI environment can start.
of system performance and availability. Among other things, this
At this stage, any user profiles still missing need to be created and
level will determine the degree of redundancy to be present in the
any other locally stored data must be transferred to the data cent-
given IT environment. This examination starts by considering the
er. The final roll-out of the thin clients is done in parallel. Based on
server hardware, but it can extend across storage devices, the
the user profiles on the server, the corresponding device groups
network itself, cooling capacity, power supply and distribution, and
and profiles should be defined in advance in the thin client man-
the like.
9/11
work, the system management solution will locate the thin clients
8. Ensuring a clean migration;
avoiding errors
by means of their respective IP or MAC address and then auto-
The following fundamental principle applies: The more detailed
matically assign their settings to them. In this way, it's possible to
the planning, the smoother the roll-out will be. If the expertise to
roll out several hundred end-user devices over a weekend.
achieve this is not available within the company itself, it's a very
agement solution. After they are physically connected to the net-
good idea to seek external support from an IT solution provider or
Notes on desktop migration
an IT systems consultant, supplier and installer. Further aspects
The desktop strategy defined in Step 1 of the migration workflow is
that ensure trouble-free migration are conducting testing as closely
all aimed at achieving a minimum TCO by replacing as many main-
as possible replicating the conditions in actual, real-world use and,
tenance-intensive fat clients with remotely manageable thin clients.
if necessary, also hiring professional support. Figure 6 shows a list
The most important selection criteria for the evaluation process
of the most frequent errors that must be avoided. If these errors are
(Step 2 in the workflow) are shown in the flow-chart depicted below:
avoided, then the IT modernization program will achieve its desired
effects. To ensure that these benefits can be enjoyed as long as
possible, the solutions selected for the server and desktop sides
do not, however, need to be proprietary ones. In other words, a
company should remain ready and willing to use future technological improvements and new technological developments. When it
comes to thin clients, this is ensured by a manufacturer that offers
regular updating of the operating system and conducts its own
software R&D program. This approach will allow users to continue
to fully exploit the potential for future system optimization.
Definition of Requirements
and Migration Strategy
1.
(user and client scenarios, TCO savings,
system availability, security, etc.)
2.
NON-C RITIC AL:
Evaluation phase
reveals new
requirements
2.
Software Evaluation
Desktop Evaluation
SBC, VDI, cloud services, etc.
(lab/field testing)
3.
4.
5.
Thin client software and hardware
(lab/field testing)
CRI T I CAL :
Pilot phase reveals
new requirements
Datacenter (re)dimensioning
(servers, storage, backup, cooling, network,
power supply/distribution)
Pilot phase / 1st roll-out
(departments, branch offices, key/power users)
Final roll-out
Fig. 5: The individual phases in migrating from client/server networks with PCs over to SBC or VDI with thin clients
10/11
Error
Causes
Results
Remedy Tips
Error during testing
• Time pressure: not enough
time for adequate testing
• Incorrect or too few user
scenarios
• No/insufficient user feedback
• Inexact evaluation
• Poor performance, security,
user experience
• Missing functionalities
• Limited TCO savings
• Test in situations as close as
possible to real-world usage
• Set up desktop and server
sides in parallel
• Seek external support from
experienced partner(s)
Mixed desktop environment
• Several end-devices per user
(e.g. virtual PC in data center
and local PC at workstation)
• Host terminals or IP telephony
not integrated in thin client
solution
• Up to twice the administrative
workload
• High maintenance and support costs due to mixed
desktop environment
• Consolidate end devices by
replacing them with universally deployable thin clients
• Convert fat clients to thin
clients using conversion
software
Short-term solution
• Proprietary solutions and protocols (e.g. zero clients: only
VDI, no SBC, etc.)
• Functionally limited thin clients
(only RDP/only ICA /only
PCoIP, etc.)
• Limits to/lack of safeguarded
investment
• Low level of technological
future-readiness
• Forgoing current and future
potentials for savings
• Employ a technologically
open/flexible, manufacturerindependent and future-proof
thin client solution
• Universal, updateable firmware
Fig. 6: Frequently occurring errors when migrating to SBC/VDI and thin clients
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