VSAM record-level sharing has multiple lock structures that are defined in the active storage management subsystem (SMS) configuration. You can define the multiple, secondary lock structures by using the parameter, Lock Set, in the SMS Storage Class definition. Using the lock set attribute, you can define an additional Coupling Facility DFSMS Lock Structure to be associated with a single SMS storage Class. DFSMS allows up to 256 Lock Sets and lock structures to be defined. Each Lock Set can contain a single lock structure name. However, the maximum number of lock structures that can be connected is between 10 and 14, depending on the MAXCAD value of IEASYSxx.

When an application opens a VSAM data set, RLS processing determines which lock structure to use by checking the storage class defined for the data set. If the storage class specifies a secondary lock structure, RLS processing uses the secondary lock structure for serializing access to records in the data set. Otherwise, RLS processing uses IGWLOCK00 for all record locking.

A secondary lock structure connection persists beyond data set closure. It is disconnected only when you restart the SMSVSAM address spaces that use the lock structure, or you delete the lock structure itself through the command VARY SMS,SMSVSAM,FORCEDELETELOCKSTRUCTURE. See z/OS MVS System Commands for details.

A failed persistent connection can exist even when the SMSVSAM address space has been terminated. the lock structure can be deleted using the VARY SMS,SMSVSAM,FORCEDELETELOCKSTRUCTURE command.