I'm nearly ready to activate DRM on a new server, but I have a worry about
copypools for disk storage.  One of the diskpools is for smaller servers
which migrate to a limited number of collocated tapes.  This pool is not
yet very active, so there are many nodes which have not yet migrated off to
tape.  I have the time and resources to copy my diskpools to tape daily,
but I wonder what sort of confusion I may be generating.

For instance, what happens to cached files that are on tape as well as
disk?  Do I get two copies? or only the one that already exists from the
backup of the tape?  What happens to a file that migrates to tape some time
after a copy is made from disk?  does it supercede the previous copy? or
are there again two copies in the copypool?  What happens in case of
disaster requiring a restore storage operation?  At this point, I really
don't know what to expect.

All assistance will be gratefully accepted.