You can also improve copy performance by correctly setting the record format level identifiers in the CPYF command.
If you are using CPYF to move data between two supposedly identical files, the record format level identifiers should be identical to optimize copy performance. If the record format level identifiers are not identical, CPYF goes through a longer code path that checks each field and column in every record. This can impact the time CPYF requires to complete the function if extensive checking is not required.
Record format level identifiers of the two files should be different if the files have different attributes. If they are not different, field and column-level checking does not perform, resulting in improper data conversions or none at all. Note that FMTOPT (*NOCHK) can be specified to avoid field and column-level checking, regardless of the value of the record format level identifiers, although certain attributes of the data (such as null values) will be lost when FMTOPT (*NOCHK) is specified.