How we move a live system
- 01
Shadow runThe new system calculates everything next to the old one and writes nothing. Your team keeps working as usual.
- 02
Daily comparisonEvery day we compare a few real records between both. Each difference gets fixed before anyone depends on it.
- 03
Numbers matchWhen both give the same result, the new system starts writing for real, a few records first.
- 04
Switch overThe old system goes read-only. Nobody had to stop working to get here.
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01 Shadow runThe new system calculates everything next to the old one and writes nothing. Your team keeps working as usual.
Current systemLive
OrderTotal
#10411,240.00
#104286.50
#1043312.00
#104447.90
#1045905.20
New systemShadow
OrderTotal
#1041…
#1042…
#1043…
#1044…
#1045…
Day 1Differences: –Writes nothing