You can add a duplicate volume using the DFSMSrmm ISPF dialog or the RMM ADDVOLUME subcommand. A duplicate volume is defined to DFSMSrmm with a unique external volume serial number and a VOL1 label that might duplicate another volume but that does not match its own external volume serial number.

For example, you have defined a pool of volumes that you use to manage duplicate volumes. You want to define a volume with the volume serial number A00001. You already have a volume with volume serial number A00001 defined to DFSMSrmm and the next available rack number in the pool is D00010, which comes from the pool that you specified for duplicate volumes.

When you use the DFSMSrmm ISPF dialog to add a volume that already exists, DFSMSrmm displays the Add Duplicate Volume panel. Follow these steps to add a volume with a duplicate volume serial number.

1. Select the option to add the volume as a duplicate or to change the existing volume to be a duplicate volume.
2. Specify a pool for the duplicate volume.
3. Press ENTER.