In TSM, files (not nodes) are associated with management classes.
When files are sent from the client to the TSM server, they are bound
to a management class, as can be controlled from the client.  Once in
TSM server storage, file management classes cannot be changed by any
command.  The only way to change the management class of a file is to
send the file to the TSM server again, with a reformulated Include
statement in effect for Backup, or an Include,Archive or ARCHMc spec
for Archive.  This discipline is in effect because enterprise level
data retention calls for retention values which are set and known at
file commit time, and which are not subsequently tinkered with by
someone beyond the client realm.  Refer to "Binding and rebinding
management classes to files" in the client manual.

   Richard Sims