In installations where DFSMShsm hosts share the same control data sets, if one host on any z/OS image accesses the control data sets in RLS mode, all hosts on all z/OS images in the HSMplex must access the control data sets in RLS mode.

DFSMShsm will fail at startup if the selected serialization mode of a starting DFSMShsm host is incompatible with the CDS serialization mode of another DFSMShsm host that is already actively using the same control data sets.