Does Top Secret have a utility that can show how full the VSAM dataset is?
Run IDCAMS with the following input:
IDCAMS LISTC ENTRIES('name') ALL
Where 'name' is the name of the VSAM file.
In the output, look for the FREESPC, as shown below in red:
DATA -------
...
STATISTICS (* - VALUE MAY BE INCORRECT)
REC-TOTAL------------446* SPLITS-CI-------------61* EXCPS-------------620939*
REC-DELETED-----------63* SPLITS-CA--------------0* EXTENTS----------------1
REC-INSERTED---------431* FREESPACE-%CI----------0 SYSTEM-TIMESTAMP:
REC-UPDATED---------2011* FREESPACE-%CA----------0 X'D62AF6CCF3EFE0D1'
REC-RETRIEVED---50683137* FREESPC----------1552384*
INDEX ------
...
STATISTICS (* - VALUE MAY BE INCORRECT)
REC-TOTAL--------------1* SPLITS-CI--------------0* EXCPS---------------3608* INDEX:
REC-DELETED------------0* SPLITS-CA--------------0* EXTENTS----------------1 LEVELS-----------------1
REC-INSERTED-----------0* FREESPACE-%CI----------0 SYSTEM-TIMESTAMP: ENTRIES/SECT----------13
REC-UPDATED----------241* FREESPACE-%CA----------0 X'D62AF6CCF3EFE0D1' SEQ-SET-RBA----------------0
REC-RETRIEVED----------0* FREESPC------------41472* HI-LEVEL-RBA---------------0