We (company) thought about this scenario,too, but we (adsm team)
revoked it.

Pro: If you don't want any other 3590, you can share the vts with other
applications.

Con: VTS is some kind of non-customizable ADSM with additional sw in a
box. In our case, adsm will flow
all buffers. You can't control any activity like migration, reclamation
etc. When migration (because
of full disk buffers) occurs when your backup window starts, all tape
processing becomes very, very sloooow.

Con2: When you have a restore, vts writes the data in his disk buffer
(1 Gig per volume?), and then adsm gets
it and writes it on the client. I expect catastrophic performance for
restores.

Con3: As you said, you will have large amounts of unused space in your
box. Reclamation may become unpredictable.

Conclusion: We have our adsm running on mvs, disk buffer ahead
(reducing needs of tape devices) and
thinking about using 3590 directly (ever heard about storagetek's
'eagle' ?). Or we are migrating to a
AIX solution with 3590. But I will nevernevernever go into something
like a vts with my adsm.

(Maybe I would if I hear some success stories on adsm with vts.)

Regards

Roger Hohmann

WestLB
Division: 009 Services
Abteilung: 001-80633
Herzogstra?e 15
D - 40217 Dusseldorf
Tel.: +49211 826 8155
mailto:roger_hohmann AT westlb DOT de