>Do you actually keep 2 copy storage pool? One offsite and on onsite?
>I'm using 3590 which never let me down and offsite, for me, means just
>another building (being the campus quite wide!). So I can get hold of the
>copy tapes in minutes.
>Apart from Murphy laws ... aren't 2 copy excessive? There are indepth
>reasons to have a Local Copy?

Yes.  3590 technology is premium; but tape is tape, and many of us have
had 3590 tapes snap or otherwise become unusable.  When that happens
and someone needs data quickly, it has to be readily available, else
the value of the expensive ADSM approach diminishes (and you aren't
taking full advantage of it if not keeping a local backup stgpool).
Your customers simply don't forget how long it took to restore their
important data, always important to them.  Skimping is simply false
economy: impress them and you'll get support for your expensive but
effective storage solution.  And again, a nearby disaster storage
location is inviting disaster.  It's also the case that you don't know
what some misinformed person in that other building might happen to do
with that bunch of tapes, or what water pipe may be quietly leaking on
them.  Disaster sites aren't absolutes, either.

Keep in mind also that unless you do electronic vaulting, sending tapes
offsite is not something you do as frequently as backups, and so it
makes sense to have an onsite copy storage pool.  Having extra 3590
tapes is far cheaper than skimping on backups and having a calamity
in which you can't restore data.  There's no feeling like when you've
failed your organization.  It's not an experience I want.
      Richard