Performance considerations
The create step of OAE execution impacts on system performance because the IMS/FP Create utility, DBFUMRI0, is run. For shadow expansions, you can improve the performance by pre-formatting the target area data sets so that the format phase of the DBFUMRI0 utility is skipped.
Once the data is copied to the extended ADS(s), there is
negligible impact upon online performance during the remainder of
the utility run.
Original expansion with EXTEND_TYPE=COPY has more impact on system performance because the IMS/FP Create utility, DBFUMRI0, is run twice.