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Migration Motivation & Goals
Migration Strategies
Migration Strategy Selection Critical Factors
Migration Strategies Overview
Big Bang
Phased Introduction
Parallel Systems
Migration Strategies Comparison
2
3
3
4
5
6
9
11
Migration Planning
Migration Definition
Migration Preparation
Migration Execution
Migration Closure
12
13
14
15
16
Migration Motivation & Goals
2
A MES migration project
represents a big endeavor
for any organization as it
involves a significant
amount of time, cost, risk
and it involves many
stakeholders within the
company. It’s critical for
the success of the
migration project to get
commitment and
engagement of the
different affected
departments.
A MES migration must be grounded
on a solid business case which
typically involves a combination of
the following three factors:
1. Take advantage of new
products & technologies (lower
total cost-of-ownership, new
functionality, easier to use,
faster).
2. Increase corporate application
harmonization with the
expectation to reduce costs by
reducing diversity and
increasing re-utilization.
3. Address software & hardware
end-of-life, addressing the risk
of running out of support in the
case of an incident or hardware
failure.
From a business point-of-view, the
expectation is that after the
migration is completed, the
organization will reap a combination
of the following benefits:
1. Cost reduction and/or
productivity improvement
derived from:
a) Total cost of ownership
reduction
b) Taking advantage of new
functionality and features
c) Deploying faster, easier to
maintain and to use systems
2. Risk reduction by ensuring
business continuity through
long-term product support
(hardware and software).
It’s worth mentioning that it may not
be possible to take the full
advantages of the new MES
immediately after migration, as it’s
often the case that a one-to-one
migration is necessary as a stepping
stone towards the migration to a
new MES. This point is elaborated in
more detail in the next chapters of
this document.
Migration Strategies
3
Table 1 - Migration types and
typical critical factors relative weight
The decision on which migration
strategy to use is driven primarily by
three factors:
1. Time - how much time does
the project take from start-to-
finish, including the pre-
migration, migration and post-
migration phases.
2. Risk - how much risk and risk
exposure (probability x cost) is
associated.
3. Cost - how much costs are
involved in the planning and
execution of the selected
strategy, including opportunity
costs (e.g.: downtime).
The three different factors above
must be weighted and analyzed in
relative terms among the different
possible migration strategy
alternatives. Each migration specific
case will weigh the three factors
above differently depending
typically on the different levels of:
1. Interdependence - how much
inter-action and interfaces
exist with other systems and
applications.
2. Automation - the level of
automation for which the MES
is responsible for.
3. Downtime Impact - how
much a unit of time that the
MES is unavailable costs to the
business.
For illustration purposes, Table 1
captures some types of MES
migration, assuming in all cases,
that there is some kind of MES in
place (even if based on paper)
and that there is some regular
production volume in place.
SYSTEM IN PLACE TYPICAL CHARACTERIZATIONTYPICAL RELATIVE
WEIGHTS
Paper or Excel Based MES
Interdependence: Low
Automation: Low
Downtime Impact: Low-to-Medium
1. Cost
2. Time
3. Risk
Stand Alone MES Application
Interdependence: Low
Automation: Low
Downtime Impact: Medium-to-High
1. Cost
2. Time
3. Risk
Integrated MES Application, Low Automation
Interdependence: High
Automation: Low
Downtime Impact: Medium-to-High
1. Cost / Risk
2. Risk / Cost
3. Time
Integrated MES Application, High Automation
Interdependence: High
Automation: High
Downtime Impact: High
1. Risk
2. Cost
3. Time
Migration Strategy
Selection Critical Factors
4
Table 2 - Migration strategies overview
Migration Strategies
Migration Strategies
Overview
There are basically three different
types of MES migration strategies,
each with its own of advantages
and disadvantages:
1. Big Bang - represents a point
in time where the old MES is
switched off and the new MES
is switch on.
2. Phased Introduction - the
new MES is progressively
introduced, either:
a) Phased by Manufacturing
Unit - area by area, step by
step, equipment by
equipment.
b) Phased by MES Function -
MES function by function.
c) Phased by Lot - lot by lot.
3. Parallel Systems - both the
old MES and the new MES
are used in parallel until
enough confidence is built in
the new MES.
Table 2 describes these migration
strategies at a high-level.
Each strategy is further detailed in
the next sections assuming for
illustration purposes that it’s
intended to maintain the existing
Operation GUI, the Equipment
Integration Layer as well as the
existing Reporting and Data
Analysis solution in a high-
automation environment.
MIGRATION STRATEGY DESCRIPTION
Big Bang Switch Off Legacy MES, Switch On New MES
Data will reside in one system only at all times
Phased Introduction
By Manufacturing Unit
Area/Step/Equipment by Area/Step/Equipment phased
introduction
Old and new MES systems will co-exist for some time, with data
split between the two systems and material being shipped from
one system to another
Phased Introduction
By MES Function
MES function-by-function (e.g.: SPC; Recipe Management or
Maintenance Management)
Old and new MES systems will co-exist for some time, but with
different functional responsibilities
Phased Introduction
By Lot
Two independent systems exist for the duration of migration. Some
lots are started in the new system while other lots are started in
legacy system
Common shared objects (Equipment, Containers, Reticles, …) must
be synchronized between the two systems
Parallel Systems
Two systems are run in parallel to make sure that everything works
as expected and after some time the new MES system is designated
as master and the legacy system is switched off
Data will reside in both systems at the same time (one system is
designated as the Master and another the Slave)
The Big Bang strategy consists of
making all the necessary
preparations and testing so that the
old MES system can be switched off
and the new MES system can be
switched on. The simplicity of this
strategy as well as the short
migration switching time makes this
strategy attractive. However,
because of all the
interdependencies and the difficulty
of re-creating all the conditions of a
live production environment, this
strategy carries a lot of risk.
Figure 1 captures the
Manufacturing IT landscape before
migration. The grey boxes represent
the old MES to be replaced by a
new one. As part of the migration,
some of the existing satellite
manufacturing applications will be
replaced by the new MES, but some
applications may remain either
retaining the complete functionality,
or just by using a subset.
Once the interfaces have been
adjusted for the new MES and the
system has been thoroughly tested
(including the migration rehearsal
procedure), once a downtime slot
has been arranged with the fab
management, the migration
procedure is carried out. The
migration procedure typically
involves data synchronization
procedures as well as some
application shutdowns,
configuration file changes and
application start-ups.
After the successful completion, the
landscape will look similar to Figure
2. Light blue boxes represent the
new MES while black boxes
represent applications or portions
of applications that have been
switched off. Immediately after the
migration, any new functionality
available in the new MES can be
used right away.
5
Migration Strategies
Big Bang
Figure 1 - Manufacturing IT
landscape before migration
ERP
Legacy Master
Data GUIOperation GUI
Legacy
MES
Other
Manufacturing
Applications
Other
Manufacturing
Applications
Equipment
Integration
Equipment
Integration
Equipment
Integration
REPORTING /
ANALYSIS
DATABASES
ERP
Other
Manufacturing
Applications
Figure 2 - Manufacturing IT
landscape after migration
Legacy Master
Data GUIOperation GUI
Legacy
MES
Other
Manufacturing
Applications
Equipment
Integration
Equipment
Integration
Equipment
Integration
New Master
Data GUI
New
MES
REPORTING /
ANALYSIS
DATABASES
ERP
Other
Manufacturing
Applications
6
Events
Client Side
Server Side
Client Calls
ERP A2A
InterfacesNew MES
ETL
REPORTING /
ANALYSIS
DATABASES
Legacy MES
LEGACY MES
DBNEW MES
DB
Routing Layer
Figure 3 - Phased Introduction
migration architecture
Migration Strategies
Phased Introduction - Phased Introduction by Manufacturing Unit
The Phased Introduction by
Manufacturing Unit consists of
slowly introducing the new MES
area by area, step by step or
equipment by equipment. Usually
starting from the first parts of the
process (area, step or equipment),
the new MES system is introduced
and the old system is switched off.
This procedure continues gradually
until the new MES system is used for
the whole factory. If for some
reason, a critical problem is
detected, the areas where the new
MES system was deployed last are
rolled back to the old MES.
With the Phased Introduction by
Manufacturing Unit migration
strategy, the client applications must
be able to work interchangeably
with either the old or the new MES
system. The best way to accomplish
this is to add a central routing layer
within the existing middleware
infrastructure. This routing layer,
depicted in Figure 3, must have the
business logic to determine when to
call one system and when to call the
other.
In some industries, like
semiconductor front-end, there is
one particular challenge which is
presented in the Phased
Introduction by Manufacturing
Unit migration strategy.
The manufacturing process itself
contains several loops (in the
case of semiconductor front-end,
one loop for each layer) as
illustrated in Figure 5. Therefore,
depending on the granularity of
the Manufacturing Unit, it can be
a case that a lot may leave one
MES system to enter another one
and then come back. While it’s
possible to handle this situation,
because of the additional
complexity, it should be avoided
whenever possible.
ERP
Other
Manufacturing
Applications
Figure 4 - Phased Introduction by
Manufacturing Unit migration strategy
Legacy Master
Data GUIOperation GUI
Legacy
MES
Other
Manufacturing
Applications
Equipment
Integration
Equipment
Integration
Equipment
Integration
New Master
Data GUI
New
MES
REPORTING /
ANALYSIS
DATABASES
ERP
Other
Manufacturing
Applications
7
Migration Strategies
Phased Introduction - Phased Introduction by Manufacturing Unit
Routing Layer
Other remarks, applicable to the
Phased Introduction by
Manufacturing Unit
(area/step/equipment):
• It’s not a requirement, but it’s
possible to freeze the master
data changes for the duration
of migration in order to avoid
master data consistency
problems.
• Because of the
interchangeability requirement,
typically, the goal of the
migration is to have the same
functionality as it existed in the
old MES system, which also
represents the minimum
common set of functionality.
• It requires a ship/receive of
Material between the two MES
systems.
• Data is spread between two
systems as the master system
changes over time, with the
new MES increasing in scope.
• Reporting (including Material
history) can be an issue, if data
is not consolidated into a single
reporting database.
NEW MES
Step 1 Step 2 Step 3
Figure 5 - Phased Introduction by
Manufacturing Unit migration strategy
in a process with loops
LEGACY MES
Step 4 Step 5 Step 6
8
Migration Strategies
Phased Introduction - Phased Introduction by MES Function
The Phased Introduction by MES
Function migration strategy is a
variation of the Phased Introduction
approach where functional portions
of the old MES are replaced by
some portions of the new MES.
This strategy deserves some words
of caution. While it’s possible to
break-up some of the MES function
so that they work well separately,
e.g.: Resource Tracking,
Maintenance Management, Recipe
Management, Carrier Management,
SPC; when it comes to Material
Tracking, there are very deep
dependencies with the Master Data
system (mainly for process flow
routing) which makes it difficult to
separate. In addition, because the
new function is introduced globally
at the fab level, these represent in
fact some form of Big-Bang,
especially when migrating the
Material Tracking functionality.
Typically this approach is
introduced in a Big Bang way when
adding new functionality or in a
Phased Introduction By
Manufacturing Unit style when
replacing existing functionality for
reasons of risk reduction.
BIG BANG PHASED INTRODUCTION PARALLEL SYSTEMS
Phased Introduction - Phased Introduction by Lot
The Phased Introduction by Lot
consists of starting some lots in the
new MES system (for instance, lots
of a particular product) while
keeping the old lots and some of
the new lots in the old MES. This
approach requires that shared
entities are modeled, synchronized
and interchangeable between the
two systems, for example: carriers,
consumables, reticles and equipment.
For the complete duration of
migration, WIP will be split into two
MES systems. In addition, control of
shared entities (e.g.: resources)
needs to be constantly delegated
from one system to another forcing
both a routing decision and a
synchronization layer to maintain
the state of the shared entities
synchronized in both systems.
This strategy can be seen as a Big
Bang for the new lots, and given the
synchronization and
interchangeability requirements, as
well as difficulty in having a baseline
and an easy rollback procedure
which carries significant risk, this
strategy is not recommended for
the great majority of the migration
scenarios.
Events
Client Side
Server Side
Client Calls
ERP A2A
InterfacesNew MES
ETL
REPORTING /
ANALYSIS
DATABASES
Legacy MES
LEGACY MES
DB
NEW MES
DB
Synchronization Layer
9
Figure 6 - Parallel Systems
migration architecture
Migration Strategies
Parallel Systems
Master - Slave
switch must be
prepared
Master - Slave
switch must be
prepared
The Parallels Systems strategy
consists in having the old and the
new MES systems running in
parallel. For the duration of the
migration, the old MES is
designated as the Master and the
new MES as the Slave. After enough
confidence has been built into the
new system, the new MES can
become the Master and the old
MES can simply be switched-off.
Instead of switching-off the old MES
when the new MES becomes the
Master it’s also possible to set it as
Slave. This provides additional
safety and flexibility but comes at
an additional cost.
This strategy requires that all the
transactions are carried out in both
systems, so a kind of
synchronization layer is required.
This layer serves as an abstraction
layer to the clients and performs all
the mapping and orchestration
required to keep both systems
synchronized. Ideally, it should
reside directly in the middleware
that links the clients to the servers,
as illustrated in Figure 6. In order to
increase the availability of the
system during the initial stages of
migration, the synchronization layer
may be designed to have the
option to succeed even if the
transaction fails in the new MES and
to report this error to the migration
team so that it can be addressed
before the migration is attempted
again. In a similar fashion, the
synchronization may be configured
to automatically switch off the
synchronization in the new MES if a
certain number of error occurs.
ERP
Other
Manufacturing
Applications
Figure 7 - Parallel Systems migration
strategy
Legacy Master
Data GUIOperation GUI
Legacy
MES
Other
Manufacturing
Applications
Equipment
Integration
Equipment
Integration
Equipment
Integration
New Master
Data GUI
New
MES
REPORTING /
ANALYSIS
DATABASES
ERP
Other
Manufacturing
Applications
10
Migration Strategies
Parallel Systems
It’s also worth mentioning that
because of the orchestration logic
of the synchronization layer, which
must call two systems, typically in a
serialized fashion for transaction
control, the clients will experience a
noticeable increase in the
transaction latency for the duration
of the migration.
Unlike the other approaches, in this
strategy data is duplicated in both
systems, so the ETL layer that brings
the data into the single-source-of-
truth (SSOT) must also have the
same switching logic as the
synchronization layer.
Both the Old MES and the New
MES will be active for the duration
of the migration as shown in Figure
7. At any time, the migration can be
rolled-back (suspended) and the
new MES can be turned off.
Other important remarks about the
Parallel Systems migration strategy:
• It’s not a requirement, but it’s
possible to freeze the master
data changes for the duration
of migration in order to avoid
master data synchronization
procedures.
• Out-of-sync systems detection
procedures must be in place.
• Migration target functionality is
the same functionality as the
old MES, which presents the
minimum common set of
functionality.
Synchronization Layer
As stated earlier in this document,
each migration case is unique.
The environment and context
conditions will determine the
appropriate migration path.
Nevertheless, it’s possible to
compare the different migration
strategies relative to each other.
That is precisely what is captured
in Table 3 which compares the
different strategies according to:
Risk, Migration Execution Time and
Cost (Effort).
Because the Phased Introduction
by MES Function can be covered
by either a partial Big Bang or by
a partial Phased Introduction by
Manufacturing Unit, the Phased
Introduction by MES Function is
not included in Table 3.
11
Table 3 - Migration strategies
comparison
Migration Strategies Comparison
BIG BANGPHASED INTRODUCTION
PARALLEL SYSTEMS
RISK
HIGH
Very difficult to test
in real production
Very difficult to
rollback
MEDIUM
Confidence is
increased over time
Somewhat easy to
rollback (phase by
phase)
LOW
Gives a lot of
confidence
Very easy to
rollback
MIGRATION
EXECUTION TIME
FASTEST
Basically, a switch-off
and switch-on
LONGEST
Each phase is a “small
migration”
MEDIUM
After enough
confidence is
gained, the switch
off – switch on can
take place
COST (EFFORT)
LOWEST $ ()
No need for
synchronization or
routing layers and
simpler migration
procedures – still
significant effort
involved
HIGH $$ ()
Requires routing layer
and requires complex
migration procedure –
effort is comparable
to Parallel Systems
HIGHEST $$$ ()
Requires
synchronization
layer (with
orchestration logic)
at application and
ETL routing layer –
effort is close to
Phased
Introduction
SUMMARY
The strategy with
highest risk, but the
shortest migration time
and lowest cost
A balanced migration
strategy
The strategy with the
lowest risk, but the
highest cost
TYPICAL
MIGRATION
SCENARIOS
Paper or Excel Based
MES
Stand Alone MES
Application
Integrated MES
Application, Low
Automation
Integrated MES
Application, High
Automation
Migration Strategies
Migration Planning
12
Regardless of the selected
migration strategy, there is a set of
steps that need to be carried out in
any case. This section includes a set
of activities that can be used as a
checklist for the migration plan and
it’s split among the following
phases:
• Migration Definition -
definition of migration scope,
target and strategy.
• Migration Preparation -
carrying out of activities to
enable migration.
• Migration Execution -
execution of the migration
strategy.
• Migration Closure - post-
migration close-down activities.
When multiple sites are
considered for migration, while
the ideal situation is to have a
target common landscape at the
end of the migration, it’s
important to bear in mind the
following:
• Each As-Is System Landscape is
different, and as such, the
migration procedure needs to
be tailored for each site. As
much as possible, what has
been developed for one site
should be re-used for the other
sites.
• The To-Be System Landscape
will most likely not be 100%
identical. This has to do on one
hand with the specifics of each
business, and on another one
with the different business
processes. A migration project
also provides an opportunity to
harmonize – when possible –
business processes in addition
to IT applications. At the end,
it’s the corporate decision,
what is the level of
harmonization that must be
achieved, balancing the need
for agility and flexibility from
the individual sites, and the
corporate need for cost
reductions by harmonizing the
systems landscape.
13
Migration Definition
Migration Planning
The Migration Definition phase is
the most important phase as it lays
the groundwork on which all
subsequent phases are based upon.
Table 4 captures the activities
associated with the Migration
Definition phase.
SEQUENCE ACTIVITY DESCRIPTION AND REMARKS
1
Capture As-Is
System
Landscape
This activity captures all the existing relevant manufacturing
applications, together with their responsibilities and inter-
dependencies.
For each site to be migrated, an As-Is System Landscape
needs to be captured.
2
Define the To-Be
System
Landscape
This activity defines which applications are replaced (partially
or totally) in the new landscape as well as the applications
that remain and the new applications that are added in the
system. It represents the desired end-system and it’s
independent of the migration strategy.
When undertaking a corporate harmonization project, this
activity has a special importance as it’s important to
understand and define what degree of harmonization is
desired; and if it’s possible to harmonize business processes
as well in addition to IT applications.
3
Migration
Strategy
Definition
This activity basically defines how the As-Is System Landscape
will be migrated to the To-Be System Landscape having in
mind, that it may take several steps to reach the end-state
goal. The strategy will basically be centered around one of the
migration strategies (Big Bang, Phased Introduction or
Parallel Systems) and it will contain:
A list of all the applications that need to be modified (with
the respective modifications)
A list of applications and utilities that need to be
developed to enable the migration (gateways,
synchronization/routing layers, data loaders, monitoring
procedures, etc.)
A list of tasks to be carried out during the migration
execution (backups, data loading, configuration file
changes, etc.)
Table 4 - Migration Definition activities
14
Migration Preparation
Migration Planning
This phase includes the execution
of all the necessary tasks required
to enable the migration execution.
A lot of the tasks have been
identified during the Migration
Strategy Definition activity of the
Migration Definition phase. Table 5
contains the typical set of activities
carried out during the Migration
Preparation phase – when the
sequence is the same it means that
the activities can be carried out in
parallel.
Table 5 - Migration Preparation activities
SEQUENCE ACTIVITY DESCRIPTION AND REMARKS
1 Systems Setup
This activity includes the hardware procurement, purchase (or
lease), installation & configuration for development, staging
and production environments for the new MES and any other
application required for migration.
1
New MES
Modeling &
Customization
This activity includes the configuration, modeling and
customization by the new MES.
1New MES
Training
This activity involves training for the different type of users:
System administrators
Power users
End users (can be delayed in time to be performed closer
to the migration execution)
1Application
Adaptation
This activity consists in adapting any existing application in
the As-Is Landscape at any level (presentation layer, business
layer, data layer) to accommodate the defined data migration
strategy.
1
Migration
Applications &
Utilities
Development
This activity consists in the development and testing of
migration specific applications and utilities necessary to
support the migration strategy, which typically includes:
Routing layers
Synchronization layers
Gateways and bridge applications
Data loading & synchronization procedures for both
master data and runtime data
Monitoring procedures
Rollback procedures
2
Integrated
Testing &
Validation
This activity consists of integrated tests for the adapted
applications together with any migration utilities which have
been developed. The goal is to make both functional and
non-functional criteria of the complete system.
3Migration
Rehearsal
This activity is used to validate the migration procedure as
well as to get the team familiar with the migration procedure
– including:
Execution of the migration steps in the right sequence
(including backups, data loading, configuration file
changes)
Getting validation that the migration steps have been
completed successfully
Getting enough information to decide whether to proceed
or to abort and rollback the migration (go/no-go decision)
Monitoring the system after migration with monitoring
procedures and validation checkpoints and deciding on
what to do if validation procedures fail
Implement a support process to respond to problems
This activity is also used to measure the time required for the
different migration procedures to complete.
15
Migration Execution
Migration Planning
This phase includes the execution
of all the activities to carry out the
real live migration. It assumes that
the necessary downtime has been
agreed with production. Table 6
captures the activities of this phase
with some of them depending on
the type of migration strategy.
Table 6 - Migration Execution activities
SEQUENCE ACTIVITY DESCRIPTION AND REMARKS
1Roll-Out & Go-
Live
This activity consists in carrying out all the steps in the
defined sequence as validated during the migration
rehearsals. There’s typically a downtime period involved with
this activity and at the end of the activity, the system must be
live so that it can be used for normal operations.
2Monitoring &
Babysitting
This activity is used to monitor closely the system as the
probability of an error occurring is very high given the
amount of changes applied to the system. The monitoring
procedures must also be followed up closely and IT personnel
must be on standby to quickly respond to problems. It may
come to the point where the migration needs to be rolled
back.
3Phase-In /
Phase-Out
For the Phased Introduction migration strategy, this activity
involves the phase-in of new manufacturing processes into
the new MES system and phase-out from the old MES system.
3 Switch-Off
For the Parallel Systems migration strategy, this activity
represents the switch off of the old MES and it is performed
after enough confidence has been built into the new MES.
4
Retirement Of
Migration
Applications &
Utilities
This activity involves the shutdown and removal of
middleware, routing and synchronization layers, gateways,
bridges, monitoring and validation software which was
developed and introduced for the single purpose of
supporting the migration. This activity needs to be well
controlled as it carries a high degree or risk.
16
Migration Closure
Migration Planning
The Migration Closure phase
consists of all the activities
necessary to properly close-down
the migration project as captured
in Table 7. It may (or may not)
include activities to activate new
functionality from the new MES
system. Note that typical project
management activities (such as
Lessons Learned and Project
Close-Down Meeting) are not
covered in this section.
Table 7 - Migration Closure activities
SEQUENCE ACTIVITY DESCRIPTION AND REMARKS
1Archive Data
From Old MES
In this activity, any relevant data from the old MES system is
archived so that it’s available when and if required. Special
care needs to be taken to ensure that the data is accessible
for the timeframe it’s required. For long term data archiving,
the usage of .TXT, .CSV, .XML for text or .TIFF for images is
recommended.
1Activate New
MES Functionality
Because most the MES migrations target a one-to-one
replacement, after the MES migration is complete, if desired,
new functionality can be activated.
2
Decommissioning
Of Unnecessary
Hardware and
Software
Unused hardware and software may be re-used for other
purposes, sold, returned (if leased/borrowed) or simply
disposed. This applies not only to hardware and software
related with the old MES, but also to any application or utility
that was required by the migration.
Critical Manufacturing provides manufacturers in highly-complex environments with a modular, scalable manufacturing execution and intelligence system that enables users to flexibly address market demands, increase efficiency and bolster reliability across the supply
chain while lowering TCO. The company is part of the Critical Group, a private group of companies founded in 1998 to provide solutions for mission and business critical information systems.
www.criticalmanufacturing.com
HQ: Porto, Portugalt: +351 229 446 927
Austin, TXt: +1-512 291 0068
Dresden, Germanyt: +49 (0)351 4188 0639
Suzhou, Chinat: +86 512 626 05371
About Critical Manufacturing
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