Very nice explanation,
Thanks you




On Wed, Jul 7, 2010 at 11:00 PM, Richard Sims <rbs AT bu DOT edu> wrote:

> Specifying 3592C would be a change from your DRIVES specification, but it
> does not necessarily represent any change over how TSM has been writing data
> to tape for you: a spec of DRIVE *should* use compression.  Specifying 3592C
> explicitly tells TSM what you want, with no ambiguities or vagueness, to
> assure what you will be getting.
>
> If your TSM clients are performing compression in sending the data to the
> TSM server, or the data was in a compressed state to start with, then what
> you are seeing is the limit of what you will get on each tape.  For
> perspective: in our shop with 3592C and a good mix of data, we typically get
> 400 - 500 GB per 3592JA tape, where native capacity is 300 GB.
>
>   Richard Sims
>
> On Jul 7, 2010, at 8:51 AM, Mehdi Salehi wrote:
>
> > I was wondering if there is a way to increase the capacity of the storage
> > pool without adding volumes. I thought changing devclass format to
> > compressed will affect the existing volume capacities and I could gain
> lots
> > of space by reclamation.
> >
> > What I conclude from your post is that only for new volumes the new
> format
> > applies, furthermore existing volumes stay unchanged "forever". Please
> > correct me if I am mistaken.
>