DFSMShsm supports VSAM record level sharing (RLS) for accessing the control data sets. RLS enables DFSMShsm to take advantage of the features of the coupling facility for CDS access.

Accessing control data sets in RLS mode reduces contention when running primary space management and automatic backup on two or more processors. DFSMShsm benefits from the serialization and data cache features of VSAM RLS and does not have to perform CDS VERIFY or buffer invalidation.