DFSMSdss uses volume serialization and data set serialization functions to ensure that data sets are not modified during the processing of DFSMSdss commands. Volume serialization is accomplished by using the RESERVE macro. Data set serialization is accomplished by using the ENQ macro and the DFSMSdss DYNALLOC function. In the case of shared DASD, volume serialization ensures that data sets are not being added, deleted, renamed, or extended from either the same processor or other processors.

You can control volume serialization with the enqueue installation exit routine. This allows other programs to access volumes while DFSMSdss is running. Volume serialization, however, cannot be overridden.

DFSMSdss supports data sets that are always open, or open for long periods of time, with backup-while-open serialization.

DFSMSdss supports backup-while-open processing for DFSMStvs and for two types of database applications: Customer Information Control System (CICS®) and information management system (IMS™).

CICS support includes both RLS CICS and non-RLS CICS backup-while-open.

DFSMStvs supports backup-while-open with or without CICS, as Backup-while-open data sets (CICS and DFSMStvs) describes.