If you are using specific pools, plan how to set up your scratch tape drives so that a correct scratch tape can be mounted promptly. The benefit of using scratch tapes is that almost any unused tape can be mounted and DFSMSrmm will record new information for the volume. However, as you become more selective about which scratch tapes are used for each non-specific volume request, the benefits of using scratch tapes decrease as your requests become more and more specific.

To make mounting tape volumes easier, consider setting aside certain tape drives for use with identified scratch pools. When using tape cartridge loaders with DFSMSrmm pooling, you need to load each drive with volumes from a single scratch pool, run them in system mode, and direct only the correct non-specific requests to them. Cartridge loaders must not be run in automatic mode because DFSMSrmm processing depends on the mount message, which is not issued when the cartridge loader is in automatic mode and a volume is already loaded. Consider defining different esoteric unit names for each of the tape drives you choose to load with scratch volumes from a single pool.

You can use the EDG_EXIT100 exit to request DFSMSrmm to disable the tape drive cartridge loader to prevent specific scratch pool requests from emptying the loaders through volume rejection. Alternatively, you can direct requests to the correct drives or run the loaders in a mode that prevents them being automatically indexed when a mount is received. Also DFSMSrmm disables the loader if a volume is rejected for a scratch request to prevent the loader from being emptied.