I remember from an IBM presentation a few years ago that the technology
behind VTS is TSM. So using a VTS library on a TSM server means stacking
the same intelligent tape management technology for two instances. This
can eliminate some of the benefits.
On one hand, when collocation is "inactivated" by VTS, access
performance to your data may drop. On the other hand, VTS uses quite a
lot of disk caching to improve performance. It depends on the structure
of a TSM servers data, whether the gain or loss in performance will be
stronger.

Best regards,
Michael
--
Michael Bartl                               mailto:michael.bartl AT cw DOT com
Michael Bartl                               mailto:michael.bartl AT cw DOT com
Office of Technology, IT Germany/Austria    Tel: +49-89-92699-806
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Bill Mansfield wrote:
>
> The fact is that TSM does not always write tapes 'til they are full.  If
> you have a bunch of small nodes using collocation or backupsets, you can
> wind up with a lot of expensive tape with little content.  Using the VTS
> would allow you to stack these nearly empty tapes onto one tape.  I'm not
> sure whether this defeats the purpose of collocation, since I'm not sure
> that the virtual tapes will stay collocated inside the VTS, though.
>
> _____________________________
> William Mansfield
> Senior Consultant
> Solution Technology, Inc
>