Hi Reggie!
This is because you don't want TSM to expire Oracle backup objects.
Oracle does not rely on TSM for backup cataloging. It uses it's own: the
Oracle Recovery Catalog. When you initiate a restore on a Oracle client, it
connects to the Oracle Recovery Catalog and it uses information in that
catalog to retrieve the backup sets and backup pieces names. With that
information the client connects to TSM to retrieve those sets and pieces.
Every now and then you schedule a cleanup script on the client which removes
obsolete sets and pieces. This removes the references from the Oracle
recovery catalog and deletes the actual data from TSM.
Kindest regards,
Eric van Loon
KLM Royal Dutch Airlines