Check out the REUSEDELAY parameter on storage pools- setting this will
prevent ADSM from scratching tapes that become empty for the amount of
time you specify.  If you do this before allowing your users on ADSM
and before expiration, migration, or reclamation runs none of your
version 1 tapes will be overwritten for the time specified.  If ADSM
puts additional data on existing tapes, or uses new scratch tapes, this
will not affect your ability to return to your V1 server.  You will
lose whatever new data was backed up, space managed or archived
since V2 was installed if you return to V1.  When you are ready to
commit to being on V2, all you have to do is change the REUSEDEALY
parameter to allow the tapes that aren't being used to return to scratch,
or you may wish to continue using that parameter and retain the ability
to restore the database for the specified number of days and have the
tapes remain intact.

Carol Trible
ADSM development