You use scratch pools with DFSMSrmm system-based scratch pooling. Define scratch volumes in rack pools and use the RMM GETVOLUME subcommand to claim them or assign them to a user. You can also use the EDG_EXIT100 exit to use rack pools or scratch pools for non-specific tape output requests.

When you define pools for use with specific groups of users or applications, you also need to consider how volumes are defined to DFSMSrmm. You can use the DFSMSrmm ISPF dialog or RMM ADDVOLUME subcommand to define volumes. To add a volume to a specific pool, provide the pool prefix when you issue the RMM ADDVOLUME subcommand or use the DFSMSrmm ISPF dialog. You only need to specify a pool prefix if the volume serial number does not start with the same characters as the pool prefix. When defining scratch volumes you will probably use volume serial numbers that match the rack numbers you include in the pool definition. When adding private volumes which come from another library you will have to specify a pool prefix. You can also use the DFSMSrmm ISPF dialog or RMM TSO CHANGEVOLUME subcommand to move an existing volume to a pool you define, so that the volume becomes part of the pool.