>If one of our on-site tapes gets physicaly destroyed, what should we do??

You *should* have an on-site copy storage pool backup, from which you
would perform a restoral of that volume's contents.  Off-site should
be for longer-term disaster backup.

You do not want to DEL VOL xxxxxx DISCARD=YES.  Sure, that will cause
a fresh backup of data from the client, but only of that client's current
data.  If the client needs a restoral of old data, it's only available
from the off-site tape.  Hence the value of the on-site copy storage pool
backup.
            Richard Sims, BU