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3.11B System Migration & Changeover (Go-live) Techniques

3.11B System Migration & Changeover (Go-live) Techniques

Changeover (Go-live) Techniques


Following are three changeover techniques for moving to new system:

Parallel Changeover


  • In parallel changeover, both new systems and old systems are operated simultaneously.

· 

  • Objective of parallel changeover is to test the reliability and performance of a new system before discontinuing the old system.

·

  • Parallel changeover reduced the risk of failed changeover.

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  • It allows the staff to get acquainted and trained on a new system.

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  • Main disadvantage of parallel changeover is the cost of running both the systems and ensuring data is consistent between the two systems.


Phased Changeover


  • In phased changeover, new modules are implemented in a phased manner.


  • This addresses the risk of complete system failure as new modules are tested and implemented in a gradual manner.


  • Following are some of the challenges of phased changeover:


  • Requirement of distinct hardware, OS, database etc. to maintain two unique environments.

  • To ensure consistency of data between new and old modules.


Abrupt Changeover 


  • In an abrupt changeover, a new system is implemented and the old system is taken off immediately.


  • It is the riskiest kind of changeover as a full system needs to be rolled back if changeover is failed.


  • Abrupt changeover is feasible where rollback is relatively easy and there is minimum impact of business processes.


Challenges related to Data Migration


  • Process of migration possesses high risk for data integrity and availability. Migration process should be thoroughly reviewed by the risk practitioner.


  • Risk practitioner should consider following points while reviewing system migration process:


  • To ensure correctness and completeness of the data transferred from old system to new system.


  • To ensure that data integrity is being maintained and there is no transcription or transposition error by transfer of data.


  • To ensure that appropriate backup is available for transferred data to address the risk of data corruption.


  • To ensure that the field/record/index and other data schema is consistent between old system and new system.


Fall back (Rollback)



  • Organization should have a structured fallback plan in place to address the risk of failure of system changeover or system migration.


  • Objective of a fallback plan is to roll back and return to the prior system.


  • Organization should have all required capability for roll back of the system before starting the changeover process



Key aspects from CRISC exam perspective

Below table covers important aspect from CRISC exam perspective:



CRISC Questions 

Possible Answer 

Who has responsibility for signing off on the accuracy and completeness of data migration of new system ?

Data owner/ User

Benefit of Parallel Cutover

Assurance that new system is working as per user requirement before discarding old system

Which system migration method has the greatest risk?

Direct cutover or Abrupt cutover


Which system migration method has the greatest redundancy?

Parallel Change


What is the greatest concern about the Direct Cutover Method?

Lack of backout plan



Self-Assessment Questions


Practice Questions - 3.11B System Migration  & Changeover (Go-live) Techniques

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