Consulting India Private Limited Legacy Information Systems Migration Challenges and Methodologies IS apoplexy Insight Innovation Agility L egacy ISs pose one of the most serious problems for large ID: 188397
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Slide1
Graceful Growth
Consulting (India) Private Limited
Legacy Information Systems:
Migration
Challenges and MethodologiesSlide2
IS apoplexy
Insight . Innovation . AgilityLegacy ISs pose one of the most serious problems for large organizationsCosts due to problems of
a single legacy IS (e.g., failures, maintenance, inappropriate functionality, lack of documentation, poor performance) can often exceed hundreds of millions of dollars per year. They are not only inordinately expensive to maintain, but also
inflexible
and
brittle
Perhaps
worse is the widespread fear that legacy ISs will, one day,
break beyond
repair. Such fears combined with a lack of techniques or technology to fix
legacy IS
problems result in
IS apoplexy
.Slide3
IS Compatibility
Insight . Innovation . Agility
3
Target model
Source model
Semantic level
Logical level
Physical level
?
?
?
Semantic
model
Logical model
Physical model
Semantic model
Logical model
Physical modelSlide4
The reality is very different
All legacy data
Legacy data
Transformations
Migration is an easy
sources are
quality is
will be simple
project with limited scope
identified
acceptable
Legacy data
All required data
Data integration
ETL and/or SQL are
formats are
exists in the
skills can easily
effective tools for
understood
legacy system
handle data
data migration
migration needs
Many new legacy
Legacy data
Transformations
Problems are found
data sources are
quality is much
are extremely
piecemeal, so migration
discovered
worse than
complex
becomes a moving target
throughout the
expected
with huge, increasing scope
project
Legacy system Legacy data is
documentation is not adequate to
out-of-date &
operate
the new
assumptions are system
incorrect
Migration is an ETL and/or SQL are
order of magnitude too sluggish to
more difficult than handle the huge
integration volume of changes
Why do so many data migration projects fail? Slide5
Classification of Migration Issues
Insight . Innovation . Agility
The issues common to software engineering projects, such as
testing and
database model selection, have been widely researched; those related specifically to migration, such as
populating the
target system’s database, have received less attention.Slide6
Although legacy information system migration is a major research issue, there are only a limited number of general
migration methods availableThe migration process as a whole is a very complex procedure encompassing many different fields of researchFollowing works in the area of Legacy Migration are discussed in this sessionThe Butterfly Methodology is being developed as
part of the MILESTONE project, an ongoing collaborative project involving Trinity College Dublin, Broadcom Eireann Research, Telecom Eireann
,
and
Ericsson which started
in July
1996
The DARWIN
project from the University of California Berkeley introduced ―Chicken little as an approach to incrementally migrate legacy systems with the constraint of interoperability between legacy and target system. This project also introduced ‘Cold Turkey’ as alternative approachInsight . Innovation . AgilityCurrent Research on Legacy MigrationSlide7
Cold Turkey
Insight . Innovation . AgilityCold Turkey
involves rewriting a legacy IS from scratch to produce the target IS using modern software techniques and hardware of the target environmentSlide8
Business conditions are ever changing so is ISSpecifications rarely existUndocumented dependencies frequently exist
Legacy ISs can be too big to cut-overManagement of Large projects is hard and they tend to bloatLateness is seldom toleratedA better system must be promisedInsight . Innovation . Agility
Cold Turkey Challenges Slide9
Chicken Little strategy
Insight . Innovation . AgilityChicken Little involves migrating the legacy IS, in place, by small incremental steps until
the desired long term objective is reached. Each step requires a relatively small resource
allocation (e.g., a few person years), a short time, and produces a specific,
small result
towards the desired goalSlide10
Insight . Innovation . Agility
Chicken Little
Methodology
Michael
Brodie
and
Michael
Stonebraker
proposed
the Chicken Little strategy, which lets LIS and target systems interoperate during migration using a mediating module, generally known as a “gateway.”The Chicken Little strategy offers an 11- step plan for cutting over from the LIS to the target system. Each step is incremental
Analyze the LIS.
Decompose the LIS structure.Design the target interface.Design the target application.
Design the target database.Install the target environment.Create and install necessary gateways.Migrate the legacy databases.Migrate the legacy applications.Migrate the legacy interfaces.Cut over to the target information systemSlide11
Insight . Innovation . Agility
The Butterfly MethodologyPhase 0: Prepare for Migration
Phase 1: Understand the semantics of the legacy system and develop the target data schema(s)Phase 2: Build up a Sample Data store, based
upon the
Target
Sample Data
, in the target
system
Phase 3:
Incrementally migrate all the components (except for data) of the legacy system to the target architecturePhase 4: Gradually migrate the legacy data into the target system and train users in target systemPhase 5: Cut-over to the completed target system.Migration using this methodology can be divided into six major phases. Each phase consists of a number of individual, normally independent, migration activities:Slide12
Investigate the different methods being used for the Legacy Information MigrationCome up with the best practices for migration projectsCome up with the check list that helps to find out if the information migration is complete both syntactically and semantically (Completeness and correctness)
Tools suggestionInsight . Innovation . Agility
GISFI (CSeON) Work ProposalSlide13
About Graceful
Growth Insight . Innovation . Agility
An organization with an objective to help organizations grow gracefully, with least pain as well as manage their operations with very high effectiveness and efficiency - by applying techniques/frameworks such as Theory of Constraints, First Time Right, Enterprise Architecture, Technology Adoption (Enterprise Mobility), etc.Slide14
Thank You
Insight . Innovation . Agility
Basavaraj.hooli@gracefulgrowth.com
;
Phone:
+91
97644 49718