The estimated capacity parameter is not used to determine when a tape is full.
The maximum capactiy parameter is used to determine when a tape is full.
Estimated capacity is used for some calculations only - things like
reclamation.  If your data is compressed on the clients, ADSM (or any other
MVS based measurement) will not show the tapes holding the amount of data that
they are advertised to hold.  Tape capacity is usually given with the
assumption that hardware compression will result in about a 3/1 compression.
Since your data is already compressed on the client, hardware compression will
not be able to reduce the size, and neither ADSM nor any of your host based
applications will give you the size of the data prior to the compression on
the client.

If you have not specified max capacity, or it is 0, the tapes will fill
until the drive signals end of tape, or ADSM calculates it to be full, using
a formula based on IBM tape drive and tape characteristics Whenever one of
these conditions are met, the tape will be considered full.

If you do specify maximum capacity, the tape will be full when either the
drive signals it has reached end of tape, or the specified capacity has been
reached -which ever comes first.

If you still feel that the tapes are not being filled to capacity, you can
set the maximum capacity parameter to the value you expect, and see if more
data is put to tape.  You will receive a warning message if the tape end is
reached before the maximum capacity value is reached.

I hope this helps,

Carol Trible
ADSM Development