North American Manufacturer – CDC Replication and Migration

Client Summary

The client is a large North American manufacturing company with several factories located across Canada and the United States. Their production operations rely heavily on continuous data replication between multiple IBM i (iSeries) systems using IBM InfoSphere Change Data Capture (CDC). This replication underpins critical factory processing and ensures that data remains consistent and available across sites. The configuration is extensive, involving numerous subscriptions, table mappings, row selections, and bidirectional replication rules that have evolved over many years.

The Challenge

By 2019, the client needed to migrate their existing on-premise CDC environment to a new cloud-based infrastructure. However, the software version in use was long out of support, and neither the current cloud platform nor any intermediate versions supported a direct upgrade path. Recreating the configuration manually was not feasible due to the sheer number of mappings and custom replication rules. The complexity of the environment, combined with time-sensitive manufacturing dependencies, meant that any disruption to replication risked interrupting factory operations. Ensuring a seamless migration without data loss or downtime was essential.

Objectives

The primary goal was to migrate the client’s existing CDC configuration to a supported cloud-based platform while preserving all replication logic and custom mappings. The project also aimed to complete the migration within a short maintenance window to avoid production impact. In 2025, the client embarked on a second migration to a new cloud provider, seeking similar stability and precision. In parallel, they also began implementing Mimix to deliver a high-availability solution for their iSeries systems, requiring adjustments to the existing CDC configuration without disrupting replication.

Technical Highlights

The client’s environment handled continuous replication of production data between multiple iSeries systems, with a high volume of transactions and complex bidirectional mappings. Maintaining data consistency and availability across all systems was critical to factory operations. The move to cloud infrastructure also introduced new recovery and high-availability considerations, particularly as the client prepared to introduce Mimix alongside CDC.

Our Approach

To overcome the unsupported software version and complex mapping challenge, a series of bespoke scripts was developed to extract the existing CDC metadata, export all mapping details, and import them directly into the new cloud-based system. This automated method eliminated the need for manual reconfiguration and preserved the integrity of all replication rules. The initial migration was completed successfully over a three-day window, with CDC fully operational in the new environment and no data loss or replication issues reported.
During the second migration in 2025, no software upgrades were required, making the process more straightforward. However, careful coordination was still needed to ensure the old iSeries system was properly shut down and that all updates were fully synchronised before the cut-over began. The client reached out directly for assistance based on prior collaboration, and support was provided through to completion.
The ongoing engagement now focuses on supporting the introduction of Mimix, ensuring CDC replication continues smoothly while the iSeries environment is adjusted to accommodate high availability.

Outcome and Benefits

Both migrations were completed successfully, with zero data loss and minimal downtime. The automated migration scripts not only accelerated the process but also eliminated the risk of human error inherent in manual reconfiguration. The client now operates on a fully supported cloud-based CDC platform, with replication running reliably across their factories. The success of the first engagement led the client to re-engage directly for the second migration in 2025, demonstrating the value of the relationship and confidence in the solution delivered. The current phase of work ensures continued stability as the client transitions to a high-availability architecture using Mimix.

Lessons Learned

Automation proved essential for managing the complexity of CDC replication environments. The project highlighted the importance of maintaining reusable migration tools and scripts for long-term system evolution. Close coordination between replication and high-availability solutions, particularly CDC and Mimix, was also critical to avoiding conflicts and maintaining continuous operations.

Follow-Up

Work continues with the client to refine the integration between CDC and Mimix, ensuring that the new high-availability configuration operates seamlessly. Future opportunities include monitoring replication performance, further tuning, and assisting with ongoing system optimisation as their cloud infrastructure matures.