Before you can use the FlashCopy® function for virtual concurrent copy, you must ensure that working space is available by allocating working space data sets (WSDS) on one or more volumes in the same, data set FlashCopy enabled, storage subsystem as the source data sets. System Data Mover (SDM) uses the working space data sets as the intermediate location for virtual concurrent copy.

The naming convention for using these working space data sets is:

hlq.ANTMAIN.FCWKnnnn

Variable hlq is the high level qualifier that you specify in the SDM PARMLIB member and nnnn is a four-digit decimal number in the value range 0000–9999. If you use both VSAM and physical sequential data sets, you must specify unique nnnn component of the name across both kinds of data sets.

The working space data sets must be cataloged. SDM performs a catalog search for usable working space data sets that match the naming convention. You must allocate data sets as single-volume, non-indexed VSAM data sets such as LDS and ESDS, or non-extended-format sequential data sets. You can use extended-format non-indexed VSAM data sets. The data sets can be SMS-managed or non-SMS-managed.

If you want to allocate secondary space, you must extend the data set by filling it with data before you start the DFSMSdss processing. System Data Mover (SDM) does not extend a working space data set. SDM holds an enqueue for the data set when the FlashCopy operation uses working space data set and releases the enqueue after FlashCopy operation finishes using the data set. You can reallocate or extend a working space data set only when SDM does not have the data set enqueued. SDM uses the new reallocated or extended data set on subsequent runs of the FlashCopy operation.

You can add more working space data sets after ANTMAIN completes the initialization process. SDM uses these data sets the first time it encounters an out-of-working-space condition. When this condition occurs during a FlashCopy operation, SDM refreshes the list of working space data sets by performing a catalog search for data set names that match the naming convention.

The LRECL and block size can be any valid combination. The VSAM control interval (CI) size can be any value. SDM uses the tracks within the data set as the target of FlashCopy operations, and you should not try to access them using normal data access methods.