Some system data sets do not require movement, either because they are allocated during system generation or because they are built at IPL time. Other system data sets, however, can be moved by DFSMSdss for various reasons.

Unless excluded, system data sets are copied. However, they generally remain open while the system is running and cannot be scratched or uncataloged because the DELETE and UNCATALOG options apply only to data sets not in use.

Frequently, system data sets are prefixed with a high-level qualifier of SYS1. The PROCESS(SYS1) keyword can be used for a data set copy operation of a SYS1 data set to move it to a preallocated target or to copy it with the DELETE option. PROCESS(SYS1) does not apply to VTOCIX or VVDS.

To limit the use of the PROCESS keyword, you need to set up a RACF® FACILITY class profile. For more information about RACF FACILITY class profiles, see z/OS Security Server RACF Security Administrator's Guide.