Before you can access the control data sets in RLS mode, they must be defined or altered to be RLS eligible. You must do this for all three control data sets (BCDS, MCDS, and OCDS). The control data sets must also be SMS-managed, using a storage class definition that indicates which coupling facility to use.

You must alter or define the control data sets using the LOG(NONE) attribute.

Example: ALTER cdsname LOG(NONE) . Whenever you alter or define the control data sets, do not use the ALL or UNDO parameters of the LOG keyword.

If it ever becomes necessary to change the control data sets back to non-RLS eligible, use the ALTER cdsname NULLIFY(LOG) command. Doing so requires that the SMSVSAM server is active. Otherwise, you must manually reset the catalog indicator for the control data sets.

To enable non-RLS read access to the control data sets when DFSMShsm is accessing them using RLS, you must define the control data sets with SHAREOPTIONS(2 3). Non-RLS read access includes functions such as EXAMINE and REPRO.