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ERP Migration

Planning for Parallel Runs: When to Use Dual-System Operations During Migration

Learn when to implement parallel runs in ERP migrations to mitigate risk, ensure data integrity, and maintain operational continuity during complex system transitions.

8 min readSysGenPro Editorial
Planning for Parallel Runs: When to Use Dual-System Operations During Migration

When to Use Dual-System Operations During ERP Migration

Parallel runs, or dual-system operations, involve running the legacy ERP and the new target system simultaneously for a defined period to validate data integrity, process accuracy, and system stability before fully decommissioning the old system. This approach is critical for high-risk migrations involving complex customizations, significant data volumes, or critical business processes where downtime is unacceptable. The primary goal is to mitigate the risk of data loss, operational disruption, and financial reporting errors by providing a safety net that allows for real-time comparison and reconciliation. However, parallel runs are resource-intensive, requiring double the infrastructure, increased user effort, and extended project timelines. Therefore, they should not be a default assumption but a strategic decision based on a thorough risk assessment. The main risks to control include data synchronization conflicts, user confusion, increased operational costs, and the potential for 'false confidence' if the parallel run is not rigorously managed. A well-planned parallel run ensures that the new system can handle real-world workloads and that all data has been accurately migrated and transformed.

Assessing the Need for a Parallel Run

Deciding whether to implement a parallel run requires a detailed analysis of the migration scope, complexity, and business impact. Not all ERP migrations require a full parallel run; some may benefit from a phased approach or a limited parallel run for specific modules. The decision should be driven by a risk matrix that evaluates the criticality of each business process, the complexity of data transformations, and the availability of rollback options. For example, a simple version upgrade within the same ERP vendor with minimal custom code may not require a parallel run, whereas a replacement of a legacy system with a new cloud-based ERP involving extensive custom integrations likely does. Key factors to consider include the volume of transactional data, the number of users affected, the regulatory requirements for data accuracy, and the availability of IT resources to support dual operations. It is essential to involve business stakeholders, IT leaders, and finance teams in this assessment to ensure that the decision aligns with business objectives and risk tolerance.

Risk Factors Requiring Parallel Operations

  • Complex data transformations involving historical data cleansing and mapping.
  • Critical business processes such as financial closing, inventory management, or order-to-cash cycles.
  • Extensive custom code or third-party integrations that have not been fully tested in a staging environment.
  • Regulatory or compliance requirements that mandate strict data accuracy and audit trails.
  • Limited rollback options due to the nature of the migration (e.g., one-way data migration).

Planning the Parallel Run Strategy

Once the decision to perform a parallel run is made, a detailed strategy must be developed to define the scope, duration, and success criteria. The strategy should specify which modules or processes will be run in parallel, the start and end dates, and the roles and responsibilities of the teams involved. It is crucial to establish clear communication channels and escalation paths to address issues that arise during the parallel run. The strategy should also include a plan for data synchronization, ensuring that data entered in the legacy system is accurately reflected in the new system, or vice versa, depending on the chosen approach. This may involve real-time synchronization, batch processing, or manual reconciliation. The duration of the parallel run should be sufficient to cover at least one full business cycle, such as a monthly financial close or a complete order-to-cash process, to validate that the new system can handle end-to-end operations.

Defining Scope and Duration

FactorConsiderationRecommendation
ScopeWhich modules/processes to includeStart with critical processes, expand if needed
DurationHow long to run in parallelMinimum one full business cycle (e.g., 30 days)
Data SyncHow data is kept consistentDefine sync frequency and conflict resolution rules
User RolesWho enters data in which systemAssign primary system for data entry to avoid duplication
Success CriteriaMetrics to measure successData accuracy, process completion, user feedback

Technical Execution and Data Synchronization

The technical execution of a parallel run involves setting up the infrastructure to support dual operations and implementing data synchronization mechanisms. This includes ensuring that both systems have the necessary hardware, software, and network resources to handle the increased load. Data synchronization is a critical component, as it ensures that data entered in one system is accurately reflected in the other. This can be achieved through real-time APIs, batch file transfers, or middleware solutions. It is essential to define clear rules for handling data conflicts, such as which system takes precedence when discrepancies arise. Additionally, monitoring tools should be deployed to track data synchronization status, identify errors, and provide real-time alerts to the IT team. Regular reconciliation reports should be generated to compare data between the two systems and identify any discrepancies that need to be resolved.

Validation and Reconciliation

Validation and reconciliation are the core activities of a parallel run, aimed at ensuring that the new system produces accurate and reliable results. This involves comparing outputs from both systems, such as financial reports, inventory levels, and order statuses, to identify any discrepancies. Discrepancies should be investigated and resolved promptly to prevent them from accumulating and causing larger issues. It is important to involve business users in the validation process, as they can provide valuable insights into whether the new system is meeting their needs and producing accurate results. Regular meetings should be held to review reconciliation results, discuss issues, and make decisions on how to proceed. The goal is to achieve a high level of confidence in the new system's ability to handle real-world operations before proceeding to cutover.

Managing Operational Overhead and User Adoption

Running two systems simultaneously increases operational overhead and can lead to user confusion and fatigue. To mitigate these risks, it is essential to provide clear guidance to users on which system to use for specific tasks and how to handle data entry. Training and support should be available to address user questions and issues. Communication is key, and regular updates should be provided to stakeholders on the progress of the parallel run and any issues that have been identified. It is also important to manage expectations, as the parallel run is a temporary measure and not a permanent solution. Users should be encouraged to provide feedback on the new system, which can be used to make improvements before cutover. By managing operational overhead and user adoption effectively, organizations can ensure a smoother transition to the new system.

Cutover and Decommissioning

The cutover phase marks the transition from parallel operations to full operation of the new system. This should be planned carefully, with a detailed cutover plan that outlines the steps, responsibilities, and timelines. The cutover plan should include a rollback plan in case issues arise that cannot be resolved quickly. Before cutover, a final data reconciliation should be performed to ensure that all data is accurate and up-to-date. The legacy system should be placed in read-only mode to prevent any further data entry, and all outstanding transactions should be processed. After cutover, the legacy system should be monitored for a short period to ensure that no issues arise, and then decommissioned. Decommissioning involves archiving data, revoking access, and disposing of hardware and software licenses. It is important to document the cutover process and any issues that were encountered for future reference.

Post-Migration Stabilization

Post-migration stabilization is the final phase of the ERP migration project, aimed at ensuring that the new system is stable and performing as expected. This involves monitoring system performance, addressing any remaining issues, and providing ongoing support to users. It is important to establish a hypercare period, where additional support is provided to address any issues that arise in the early days of operation. Regular reviews should be conducted to assess the system's performance and identify areas for improvement. Feedback from users should be collected and used to make enhancements to the system. By focusing on post-migration stabilization, organizations can ensure a successful transition to the new ERP system and maximize the benefits of the investment.

Key Decision Criteria for Parallel Runs

CriteriaHigh Risk (Parallel Run Recommended)Low Risk (Parallel Run Optional)
Data ComplexityExtensive transformations, historical dataSimple mapping, minimal historical data
Process CriticalityFinancial closing, regulatory reportingInternal reporting, non-critical processes
CustomizationHeavy custom code, third-party integrationsStandard configuration, minimal custom code
Rollback OptionNo easy rollback, one-way migrationEasy rollback, reversible migration
Resource AvailabilityLimited IT resources, high user loadAbundant IT resources, low user load

Conclusion

Parallel runs are a powerful tool for mitigating risk in ERP migrations, but they are not a one-size-fits-all solution. The decision to use dual-system operations should be based on a thorough assessment of the migration's complexity, risk, and business impact. By carefully planning the parallel run strategy, managing operational overhead, and validating data accuracy, organizations can ensure a successful transition to the new ERP system. It is essential to involve all stakeholders, communicate clearly, and monitor progress closely to address any issues that arise. With a well-executed parallel run, organizations can gain the confidence needed to proceed with cutover and decommissioning, ultimately achieving the desired benefits of the ERP migration.

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SysGenPro Editorial

SysGenPro Editorial

Platform & solutions team

Practical guidance on ERP, AI automation, cloud deployment and enterprise transformation from the SysGenPro team.

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Frequently asked questions

Common questions on this topic. Talk to our team for anything specific to your business.

01What is the main risk of not performing a parallel run?

The main risk is undetected data integrity issues or process failures that only become apparent after cutover, leading to operational disruption, financial errors, or compliance violations.

02How long does a typical ERP parallel run take?

A typical parallel run lasts for at least one full business cycle, such as 30 days, to ensure that all processes are validated under real-world conditions.

03Can you run a parallel run for only specific modules?

Yes, a phased parallel run can be implemented for specific critical modules, such as finance or inventory, while other modules are cut over earlier.

04What are the costs associated with dual-system operations?

Costs include increased infrastructure, additional IT support, user training, and the time spent on data reconciliation and validation.

05How do you handle data conflicts during a parallel run?

Data conflicts are handled by defining clear precedence rules, such as giving priority to the new system, and resolving discrepancies through manual review or automated scripts.

06Is a parallel run required for cloud ERP migrations?

Not always, but it is recommended for complex migrations involving significant data transformations or custom integrations to ensure data accuracy and process stability.

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