The migration plan looks like the following sequence:
**I) Preparation**
# update write logic so that it would write to both schemas (wb_terms and normalized one) on configuration (Task T219297 and T219295)
**II) Property Terms migration (small footprint on time and size)**
# write a maintenance scripts for populating the normalized tables with property terms (Task T219296)
# turn on configuration for writing to both schemas for properties & run the maintenance script for properties (part of Checkpoint T219301)
`estimated increase in disk space usage = ration properties/items within current wb_terms * current disk usage of wb_terms * ration of data size before/after normalization (accord. to test run)`
`estimated increase in disk space usage = 0.0001 * 846GB * 0.2 = ~17.5MB`
**III) Item Terms migration (big footprint on time and size)**
# write a maintenance scripts for populating the normalized tables with item terms (part of Checkpoint T219122)
# turn on configuration for writing to both schemas for items & run the maintenance script for items (part of Checkpoint T219123)