Ensure that you are using global resource serialization (GRS), or an equivalent product, to convert hardware RESERVE/RELEASE requests to data set ENQUEUEs. Your DASD buffer requirements might increase significantly if you do not use GRS or an equivalent product. Use the interval migration function of DFSMShsm to manage the DASD buffer. In environments that have GRS active, interval migration or primary space management immediately moves all data sets with a direct-to-migration-level-2 management class to tape. However, if you have multiple systems, if GRS is not active, these data sets must be at least two days old before interval migration or primary space management migrates the data sets to tape.

For a single processor with GRS not active, data sets that should be written directly to migration level 2 must be at least one day old before being migrated by DFSMShsm.

When you use GRS to control data set integrity, specify USERDATASETSERIALIZATION in the DFSMShsm PARMLIB.