for our dfs backups we use the buta client which allows us to backup
filesets, thereby improving
the performance of nightly backups.  You are allowed a lot of connections,
and it allows for better segmentation
of types of backups (i.e. daily, weekly, quarterly, yearly).  A lot is
needed on the dce/dfs end to schedule this, but
it works out well in the long run.  Our nightly backups run about 25-40
gigs and rarely does it take more than
6 hours.

Jason Phebus
Workbench Services
IBM RTP
phebus AT us.ibm DOT com