NZD Migration Scenario
Near-Zero Downtime (NZD) is a special scenario within the Migration scenario.
The goal of NZD is to minimize the data volume required for processing during the system outage. The less data that needs to be processed within the outage, the shorter the required time for the business disruption.
The NZD processing introduces two new task types: the delta read and the delta delete. The delta read processes changes collected by DTS delta mode.
The delta delete task cleans up already inserted data. The data to be deleted is marked by the delta read task.
The processing of delta tasks is therefore executed before the system outage. The delta processing can be repeated multiple times. This might be required for tables with a larger amount of changes.