We also have a VTS and decided to use native Magstar instead.  You may have
something when you mention a lot of reclaimation would occur using the VTS
with ADSM.  We decided it was a bad idea to use the VTS  with ADSM since it
would cause a large amount of recalls for logical volumes back to the
volume cache.  Since ADSM appends to a tape until its full, you would have
to have a very long cache residency time for your VTS virtual volumes
containing ADSM data to keep backend recalls to a minimum.  Native Magstar
is ideal for ADSM since it is very good at keeping tapes full.  Unless your
VTS cache is huge or almost exclusively dedicated to ADSM I think native
Magstar is a better bet.

In regards to your two other MVS related questions, the suffix for ADSM MVS
datasets names is BFS.  So if you use SYS2 for prefix in your device class
definition the result would be SYS2.BFS.  I'm more familiar with VTS and
CA-1 but I assume the 3494 is the same as far as making them aware of each
other.  I believe the cartridge entry exit CBRUXENT is required for volume
status sychronization I.E scratch or not.  I think there is a write up on
3495 support in the CA-1 System Guide which are the same requirements for
3494 support.  Would have to look it up to give you more specifics.  If you
have the CA-1 manuals on CD-ROM you can search on 3495 to find it. We don't
vault our ADSM tapes so I can't help you much there.

Hope this helps,

Jeff Connor
Niagara Mohawk Power Corp.
Syracuse NY






Thomas Denier <Thomas.Denier AT MAIL.TJU DOT EDU> on 12/02/98 10:23:56 AM

Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>

To:   ADSM-L AT VM.MARIST DOT EDU
cc:    (bcc: Jeffrey P Connor/IT/NMPC)
Subject:  ADSM and Virtual Tape Server




My site is planning to install an ADSM Version 3 server on an MVS system.
We
are also planning to install a 3494 automatic tape library with a VTS
(Virtual
Tape Server). Current plans call for sending incoming backup data to
primary
tape storage pools using the VTS. The disk cache on the VTS is almost
certainly large enough to keep new backup data on disk until a COPY STGPOOL
is
done to produce off-site backups, and probably large enough to keep
partially
filled virtual tapes on disk until ADSM puts more data on them.

I am a bit nervous about the amount of behind the scenes tape activity this
approach will entail. Each time ADSM adds data to a partially filled
virtual
volume, the real tape space occupied by the old version of the virtual
volume
will go out of use. I would expect this to end up triggering large amounts
of
VTS tape reclamation activity. I am also nervous about the two-tiered
reclamation we will be doing as ADSM clears virtual volumes and the VTS
eventually clears the real volumes formerly occupied by the reclaimed
virtual
volumes.

What are the pros and cons of using a VTS for ADSM primary storage pools?