Use case — ERP & Legacy Migration
Leaving a Legacy Warehouse without turning off the lights.
Many applications stay switched on for years after being replaced, because no one dares lose what they contain. The question isn't technical: it's about continuity and proof. As long as the organization can't demonstrate that the history has been carried over and is consistent, it won't switch anything off.
The situation
Why the old system stays switched on
Licenses keep running, expertise leaves, and a few times a year an audit or a dispute forces someone to dig up information from a system that no one uses day-to-day anymore.
The difficulty isn't extracting the data, but everything around it: knowing what must be kept and for how long, ensuring existing reports keep working during the migration, and being able to explain a discrepancy between old and new. Without these three elements, the decision to decommission gets postponed indefinitely.
The method
Five steps, one domain at a time
The progression is the same for every domain. What changes is the difficulty: we start with a scope that has real value and manageable complexity.
- 01
Map and prioritize
Inventory of sources, reports and their consumers. We identify the domains with the highest business value and manageable complexity.
- 02
Build the domain's Raw Vault
The relevant sources are integrated and historized as-is, without immediately disrupting existing reporting, which keeps running on the old pipeline.
- 03
Rebuild marts and reconcile
Metrics are recalculated from the vault and compared against those from the legacy environment. Discrepancies are made visible and explained, never hidden.
- 04
Move consumers over gradually
Reports and users switch over once the new results are reviewed and accepted by the business. The old pipeline remains available for the agreed period.
- 05
Decommission and chain
The legacy domain is only decommissioned once the new data pipeline is reliable. The team then moves on to the next domain, with the approach already proven.
What you get
A searchable history, a traceable answer, and one less system to maintain.
Migrated data remains queryable through outputs built for that purpose, without restarting the original application. Lineage and documentation explain where a piece of information comes from and how it was transformed.
Once the chain is validated, the old system can be decommissioned, along with the operational burden and risk exposure that came with it. The scope migrated is an explicit choice, set according to retention obligations and actual usage.
Frequently asked questions
What Teams Ask Us For
Do we need to start over?
No, and that's the first decision to make. Scope is set according to retention obligations and actual usage, not out of caution.
How do you demonstrate that the migration is consistent?
Through count and consistency checks between the source system and the platform, documented and repeatable. That evidence is what enables the decommissioning decision.
Can we handle multiple applications?
Yes, one after the other. Common business entities are matched by their business keys, which avoids rebuilding a silo for each application.
Is this tied to replacing the ERP itself?
The two are often combined: the new system carries the processes, the platform carries the history. These are two distinct efforts that are best not confused.
Next step