Enabling stacked volume support

With DFSMSrmm stacked volume support enabled, you can manage the movement of logical volumes using stacked volumes. Without stacked volume support enabled, you can define and list stacked volumes using the DFSMSrmm ADDVOLUME TSO subcommand with the TYPE(STACKED) operand. DFSMSrmm inventory management ignores any stacked volumes that you have defined and uses just the container name in the volume records.

Prior to enabling stacked volume support, consider these conditions:

You cannot disable stacked volume support once it is enabled.
Do not enable support unless all systems using a control data set support stacked volumes. If the control data set is shared with a lower level and support is enabled you can create inconsistent information in the control data set. Correct inconsistencies by using the DFSMSrmm EDGUTIL MEND(VOLUME) utility before you can run inventory management.

To enable stacked volume support, perform these tasks:

Update all systems sharing a control data set to the DFSMSrmm level of code containing stacked volume support.
If you have stacked volumes defined to DFSMSrmm, but not as stacked volumes, you need to change volume information. Use the RMM SEARCHVOLUME subcommand to set the correct location information and volume type for non-exported stacked volumes. You need to do this before running EDGUTIL MEND(VOLUME). Although the EDGUTIL processing changes the volume type to stacked, it does not set the correct location information unless the stacked volume is exported and contains volumes.
You can use the RMM SEARCHVOLUME subcommand to build the command to change the volumes:
```
RMM SEARCHVOLUME VOLUME(ST*) OWNER(*) LIMIT(*) -
 CLIST('RMM CHANGEVOLUME ',' TYPE(STACKED) LOCATION(vts_name) NORACK')
```
Use EDGUTIL UPDATE with the STACKEDVOLUME(YES) operand on the CONTROL statement of the SYSIN file.
Once you have enabled support, you can use EDGUTIL with VERIFY(VOLUME) to check if the container information is consistent.
Use the RMM LISTCONTROL CNTL subcommand to display the status of support.
If support shows MIXED, run the EDGUTIL MEND(VOLUME) utility to make the container information consistent. The inconsistency is the result of having container information in volume records in the control data set.

During EDGUTIL MEND(VOLUME) processing, DFSMSrmm creates the necessary stacked volumes if you have not previously defined them to DFSMSrmm using the DFSMSrmm TSO subcommands.

During EDGUTIL MEND(VOLUME) processing, DFSMSrmm converts each volume in a container as being in the container instead of a DFSMSrmm location. The location and bin number information in volumes that are in a container is removed, and bins returned to empty status. A bin number is assigned to the stacked volume if the location it is in is bin managed. The bin number is selected from one of the contained volumes by using location priority. The bin number choice should reflect the processing used by EDGRPTD in producing movement reports before stacked volume support is enabled.

From now on, when you run storage location processing, DFSMSrmm moves the stacked volumes based on the required location and priority of the contained logical volumes.
Update your procedures used to export or import logical volumes to use the required location of the logical volume instead of using the destination. See DFSMSrmm support for stacked volumes when stacked volume support is enabled.