A copy that requires maintenance of a keyed sequence access path is slower than a copy from or to an arrival sequence access path.
You can improve copy performance if you reorganize the from-file so that its arrival sequence is the same as its keyed sequence access path. You can also improve copy performance if you select records by using the FROMRCD or TORCD parameter so that the keyed sequence access path is not used.
Create fewer logical access paths over the to-file. This improves copy performance because the copy process does not need to update as many access paths.
The smaller the length of the records within the file, the faster the copy.