ARC0125I

Explanation
 An ADDVOL command was issued to add a volume to DFSMShsm control.
The command failed because the unit type specified in the command
was invalid or a tape volume was specified as a primary or migration
level 1 volume. Tape volumes are only supported as backup, dump, or
migration level 2 volumes. Dump volumes cannot be DASD volumes. The
volume serial number is volser and the invalid
unit type is unittype.

System action
 The command ends. DFSMShsm processing continues.

Programmer response
 Reissue the command with the desired unit
type correctly specified. Be sure this unit type is supported by DFSMShsm.
 Note: Reel-type tapes associated with devices prior to 3480 are no
longer supported by DFSMShsm for backup and migration functions.
However, dump volumes can still use reel-type tapes.

Source
 DFSMShsm