Perform this step once for each RMMplex, or for each z/OS image.

Create the DFSMSrmm control data set, a VSAM key-sequenced data set that contains the complete inventory of the removable media library. DFSMSrmm records all changes made to the inventory, such as adding or deleting volumes, in the control data set. The DFSMSrmm control data set can be allocated in the extended addressing space of an extended address volume. The DFSMSrmm CDS is eligible for, and supports, CA Reclaim.

You can create the control data set for each RMMplex or for each z/OS image. If you have a control data set for each z/OS image, each control data set only contains information for that system. DFSMSrmm cannot track tapes that are accidentally moved to another system that has a different control data set.

Recommendation: Create one control data set for each RMMplex. Sharing the control data set across systems allows DFSMSrmm to keep all tape usage information in one place.