To change the size of the DFSMSrmm control data set or journal (either to make the data sets larger or smaller), use the procedures documented in this topic. The basic procedure is to use backup and recovery, but the method selected depends on whether you have a new volume available for the new control data set. If you use the existing volume and must delete the existing data set to allocate one of a new size, follow the procedure documented in Backing up the DFSMSrmm control data set and journal and Restoring the control data set with forward recovery. If you use a new volume, follow the procedure documented in Moving the control data set and journal to a different device. When you allocate the new data sets, make them the required size by either increasing or decreasing the size based on your requirements.