I'd love to have a couple vtl's . . . .

"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 06/08/2007
05:34:03 PM:
>
> Yes, tape is still cheaper, but if you compare the price of a large VTL
> with de-dupe to an equivalently sized tape library, they'll be a lot
> closer than you think

I'd love to have a couple vtl's.  When we've priced them out they come
out to be much more costly (several times) that of tape for our
environment.  We keep lots of old/stale data around which drives seems
to drive the cost of the VTL way up.  I was hoping possibly use a vtl
for only primary data with the new feature of TSM v5.4, but that's not
going to work out.

> The second thing VTLs bring to the table is hardware compression.

> Then, of course, there's de-dupe, which most surveys are showing to be
> the got-to-have technology of this year.  It's here.  It's real.  And it
> really does shrink the amount of disk you need to use by a factor of
> 10-20:1, and even more depending on how you do your backups.

Agreed.  I'm convinced that compression and de-dupe is what you're
purchasing in a vtl as opposed to just straight disk.  It would be
a lot cleaper to just purchase disk, but then no compression and
no de-dupe.

I personal opinion is that VTL's are a stop-gap solution.  I think
compression and de-dupe have much wider application within a normal
disk subsystem where it could apply to a much wider range of
situations.  A long time ago a company we purchased had
a old STK Iceberg disk subsystem . . .yea, the one with with log
based writes like NetApp except with hardware compression.  The
guys who used it have nothing but praise for it (although it had
it's problems!!!).

NetApp is adding de-dupe to their disk systems . . . .now
if they would only add hdwr compression . . .

> The reason that VTL/disk can outperform tape is that
> disk can go whatever speed your backup is going and tape cannot.

This is the bit problem I see with Tape.  It seems to me that the
latest generations of tape drives have rated speeds that almost
defy the any ability to supply them with data.  I almost which
I could purchase a modern tape drive that actually was slower.

> Most environments never get anywhere near their tape's capabilities and
> about half or so are getting a small fraction of their tape drive's
> capabilities.

Exactly . . . .

> Just my $.02.
>
> ---
> W. Curtis Preston
>
>


Add my $.02

Rick


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