To prevent tape failures from effecting a restore, you will use a copy
storage pool and always have at least two copies of the data, one in your
robot and one at your off-site storage facility.

If you user has rapid restore requirements, you can collocate his data on a
single cartridge during the backup process.  In fact, this is the only way
to guarantee his data will be on only one (or possibly two depending on how
much data) cartridge.  ADSM works at the file level not at the disk level.
 So all files are maintained by ADSM as single objects.  If your tape
storage pool is not collocated, you can't depend on all of the files from
one client being on one tape.

ADSM is different.  Trying to apply the traditional backup paradigm to it
is difficult.  It wasn't designed to work that way and it doesn't need to.
 There are ample features to guarantee the safe restoration of any data.

Kelly