Legacy ERP modernization with zero-downtime data migration
A ten-year-old ERP system, patched over and over, was migrated to a modern architecture without losing any data.
MigrationPostgreSQLLegacy Modernization
Situation
A retail and distribution company had run the same ERP system for over a decade. It had become closed to new features — the developers who built it had moved on, documentation was incomplete, and the database schema had grown inconsistent over the years. Yet the system held the company's entire stock, pricing, and discount history — shutting it down and starting over was not an option.
Solution
We first built a comprehensive inventory of the existing system: the database schema, business rules, discount/pricing logic, and integrations were documented one by one. On top of that inventory, we built a phased migration plan:
- The new system was launched to run in parallel with the old one
- Data migration happened module by module, each with validation reports
- Pricing/discount structures and stock history were cross-checked with separate scripts
- The final cutover happened during a planned maintenance window
Results
- A full migration with zero data loss
- Downtime was limited to the planned maintenance window
- The new system can now be updated regularly through a Docker- and Jenkins-based CI/CD pipeline
- The team can now deliver new feature requests within weeks instead of months