Additional CKDS performance considerations

IBM recommends that installations that deploy a fixed-length format CKDS with millions of symmetric keys do not enable CKDS MAC authentication or disable it if it is already enabled. CKDS MAC authentication adds an additional coprocessor request for each VSAM data set read/write operation. There is a significant performance implication for CKDS MAC authentication that would be greatly magnified with such a large CKDS.