We have seen the same failure mode more times than we would like. A migration project runs well through development and testing. The team is confident. The data looks clean. Then go-live weekend arrives and the cutover load takes three times as long as planned, data quality issues surface that nobody knew existed, and the team is making decisions under time pressure that should have been made weeks earlier.
In almost every case, the root cause is the same: the trial run was skipped, shortened, or treated as a formality. When we ask why, the answer is usually ‘we did not have time’ or ‘the environment was not ready.’ Neither of those is acceptable, because the cost of skipping the trial run is always higher than the cost of doing it.
A well-run EBS to Fusion customer migration does not happen in a single load. It is structured across four waves, each with a specific purpose and a formal gate before the next one begins.
What the trial run actually tells you
The trial run answers questions that no amount of development testing can answer. How long does the ESS job actually take for your volume? Not an estimate based on a sample — the actual duration on
production-like data. How many records surface data quality issues that only appear at scale? What Fusion configuration gaps exist that only become visible when real data hits real validation rules?
We have seen trial runs surface issues as significant as AutoAccounting rules that work for domestic customers but fail for international ones, payment term names that exist in EBS but were created with slightly different names in Fusion, and primary Bill-To site use violations affecting 8% of the customer population. All of those are fixable in two weeks. None of them are fixable at 3am on go-live weekend.
The trial run also produces the single most valuable artefact in the cutover plan: actual measured timing for every step.Wave 3 cutover runs on a fixed downtime window. If you do not know how long each load actually takes, your window calculation is fiction. The trial run turns that fiction into a plan.
The cutover plan is built on trial run timings. Without a trial run, you are not planning — you are guessing.What good looks like across all four waves
A well-run migration feels almost uneventful on go-live weekend. The team knows exactly what to do and in what order. The FBDI files are already generated. The reconciliation scripts are already tested. The go/no-go criteria are already agreed. The rollback plan is already documented. The cutover runs on measured timings, not instinct.
That apparent smoothness is the product of everything that happened in Waves 0, 1, and 2. It is the reward for the data profiling that happened before any SQL was written. For the validation framework that caught problems in staging rather than in Fusion. For the trial run that surfaced configuration gaps in a controlled environment. For the governance artefacts that meant every decision was already made before the pressure was on.
Customer migration done well is invisible. Go-live happens, users log into Fusion, their customers are there — correct, complete, reconciled. The complexity that went into making that happen is what this series has been about.
Thank you for following the series. If any of these posts raised questions about your own migration programme, or if you are in the early stages of planning an EBS to Fusion Cloud migration, we would welcome the conversation.
Let's talk. BizInsight Con sulting works with organisations planning and executing EBS to Oracle Fusion Cloud migrations. We bring architecture,methodology, and production experience to every engagement.
