You should make two copies of your data anyway.  Since ADSM, by default,
only has a single copy of any file, you need to have another copy in case
of media failure.  This extra copy will also be your off-site copy.  To
create this second copy, you use a copy storage pool.  To move a copy of
data from the primary pool to the copy pool you will use the backup stg
command.  This is normally scheduled and occurs before you migrate data
from your disk pool to tape.  The only data that is moved on a daily basis
using backup stg is the newly arrived data.  So, this backup is not a
complete copy of everything in the primary pool, but an incremental backup.

The days of having a new, complete set of your data everyweek are over.
 Only changed data is moved.  This changed data is ideally stored to tape
twice with one set of tapes being removed to the off-site on a daily basis.
 I believe you will find most ADSM shops are using this approach.  Perhaps
the tape movement occurs somewhat less than once per day, but often enough
to provide safety.

ADSM is a different beasty, as I've been known to say in the past.  I
strongly recommend a training class for folks not familiar with the
product.  Those things you think you know about backup are turned topsy
turvy with ADSM.

Thanks,

Kelly J. Lipp
Storage Solutions Specialists, Inc.
www.storsol.com
lipp AT storsol DOT com
(719)531-5926