Moving from the old system.
WHAT TO DECIDE FIRST
What actually needs to move.
WHAT USUALLY MUST
Open balances Open transactions Master data Recent history
WHAT USUALLY NEED NOT
Full transaction history Records for inactive entities Data nobody has used
WHY LIMITING IT MATTERS
Migration effort and risk scale with volume.
WHAT TO DO WITH HISTORY NOT MIGRATED
Retain the old system, read-only, or archive extracts.
WHY THAT IS FREQUENTLY BETTER
It is cheaper than transforming history into a structure it does not fit.
WHAT TO ESTABLISH
How long the old system must remain accessible.
WHY
Statutory retention may require years.
WHAT THE PHASES ARE
- Profiling: understanding what exists
- Cleansing: correcting it
- Mapping: deciding where it goes
- Transformation: converting it
- Loading: putting it in
- Verification: confirming it is right
WHAT TO DO SEVERAL TIMES
All of it, as trial runs.
WHY
The first attempt always reveals problems.
WHAT TO PLAN
At least three trial migrations.
WHAT THE FINAL ONE IS
The cutover, performed against a tested procedure.
