Parameters for the migration level 1 ADDVOL commands

The example below shows parameters used with the the MIGRATIONLEVEL1 parameter:

ADDVOL  1 ML1001  2 UNIT(3390) -
        3 MIGRATION(MIGRATIONLEVEL1 -
        SMALLDATASETPACKING) THRESHOLD(90)

1 - The first parameter of the ADDVOL command is a positional required parameter that specifies the volume serial number of the volume being added to DFSMShsm. In Figure 1, migration level 1 volumes are identified by volume serial numbers that start with ML1.
2 - The second parameter of the ADDVOL command is a required parameter that specifies the unit type of the volume. For our example, all ML1 volumes are 3390s.
3 - The third parameter is a required parameter that specifies that the volume is being added as a migration volume. This parameter has subparameters that specify the kind of migration volume and the presence of a small-data-set-packing (SDSP) data set on the volume. If you specify SMALLDATASETPACKING, the volume must contain a VSAM key-sequenced data set to be used as the SDSP data set. See DFSMShsm small-data-set-packing data set facility for details about how to allocate the SDSP data set.
The number of SDSP data sets defined must be at least equal to the maximum number of concurrent volume migration tasks that could be executing in your complex. Additional SDSPs are recommended for RECALL processing and ABARS processing and if some SDSPs should become full during migration.
The THRESHOLD parameter in our ADDVOL command examples specifies the level of occupancy that signals the system to migrate data sets from migration level 1 volumes to migration level 2 volumes. If you want DFSMShsm to do automatic migration from level 1 to level 2 volumes, you must specify the occupancy thresholds for the migration level 1 volumes.

Note:

Automatic secondary space management determines whether to perform level 1 to level 2 migration by checking to see if any migration level 1 volume has an occupancy that is equal to or greater than its threshold. DFSMShsm migrates all eligible data sets from all migration level 1 volumes to migration level 2 volumes.
If the volume is being defined as a migration level 1 OVERFLOW volume then the threshold parameter is ignored. Use the SETSYS ML1OVERFLOW(THRESHOLD(nn)) command to specify the threshold for the entire OVERFLOW volume pool.
If you're adding volumes in an HSMplex environment, and those added volumes will be managed by each host in an HSMplex, then be sure to issue the ADDVOL on each system that will manage that volume.

For more information about level 1 to level 2 migration, see z/OS DFSMShsm Storage Administration.

In specifying the threshold parameter, you want to maintain equal free space on all of your migration level 1 volumes. If you use different device types for migration level 1 volumes, you must calculate the appropriate percentages that will make the same amount of free space available on each device type. For example, if you have a mixture of 3390 models 1 and 2, you might specify 88% for model 1 (92M) and 94% for model 2 (96M).