>> On Mon, 16 Jul 2007 02:20:46 -0700, Francisco Molero <fmolero AT YAHOO DOT 
>> COM> said:

> Hi, I don't think HSM is a bad product, I think you need to clarify
> what the product does. [...]

Hrm.  I agree that it does what it says it does, so I think we agree
that it's not a bad product.

Instead, I think the fit between 'what it says it does' and the
featureset usually associated with the term "Heirarchical storage
management" is casual at best.

> 1.- Retversion for archvie copy group 9999. Or how many days you can
          store a file without activity.

means you end up storing a number of copies related to the frequency
of -access-, not the frequency of -change-.  I consider this a
game-breaker.


So you write the file,
Then you back up the file,
Then you migrate the file.
then you back up the stub.

then you read the file:
   and back it up again.
   and migrate it again.
   and back up the stub again.

then you read the file:
   and back it up again.
   and migrate it again.
   and back up the stub again.

Each of the migrated versions stays around forever, or for however
long you decided you want to keep the migrated bits of HSM.  The
successive retrieved versions are also backed up, which means you
could have quite a few identical versions in the pipelines.  These
will age out in time, so they don't constitute the permanent load that
the archive bits do.

Because of this, the storage associated with a single file can just
grow without bounds.


- Allen S. Rout