From one system in the SMS complex, issue the T SMS=xx command, where xx identifies IGDSMSxx as the SMS initialization control member of SYS1.PARMLIB. SMS uses the ACDS and COMMDS identified in IGDSMSxx to manage storage. Because the initial ACDS and COMMDS are empty, the system is activated with a null configuration. Keep in mind that a null configuration is only intended as a migration path.
For additional information, see z/OS MVS Initialization and Tuning Guide.