>> On Wed, 13 Jun 2007 08:43:43 -0400, "Johnson, Milton" <milton.johnson AT 
>> CITI DOT COM> said:

> The VTL is a Sepaton S2100-ES and yes it is disk only.

> I don't see the benefit that a "tape backed" system would bring, how
> does that really differ from a physical tape ATL with TSM providing
> a DISKPOOL front end?

Well, exactly. :)

But the distinction I wanted to make clear was: if you've decided to
store all your data on disk, then TSM has all the primitives necessary
to make that disk manageable, and you can discard the intermediate
appliance that makes the disk pretend to be a bunch of tape drives.
That's what everyone's getting at when they talk about FILE
devclasses.

So if you bought 23 TB of slow disk plus a pretend-im-tape-box, then
the tape box was a waste, if you're using TSM.  If you're using
something without TSM's volume primitives, it could be extremely
important.


- Allen S. Rout