>2.) pls give me vendor / machine type of VTLs which does compression 
>without performance impacts.

Several of them are now using hardware compression.  They use the same
chip as the tape drives do, therefore, they get what you're asking for.
(I don't want to give vendor names cause the names will change
tomorrow.)

>3.) you need compare the same technology. You need compare a FC Disk 
>Subsystems, like DS4000, with a VTL, then you get the same performance 
>(maybe even more) from a File Device Type as from a VTL.

With a WHOLE LOT more management and none of the other cool stuff we're
talking about.

>4.)current de-dups does not bring enough performance for most of the 
>environments, and in addition, most vendors have just announced it, but

>does not have it ready for GA yet.

You hit the nail on the head there.  Not sure if I'd say "most"
environments, but definitely "many."  If you look at the stats, most
environments are actually quite small and will work with just about
anything on the market.  The currently GA de-dupe products (Data Domain,
HDS, Diligent, NetApp) support 200-300 MB/s.  That's 6-9 TB in an
eight-hour window.  That'll meet a LOT of people's needs.

Falconstor & SEPATON are currently in limited availability (think
something just beyond Beta).  That doesn't necessarily mean it's buggy.
It's a new technology and they want to know what customers should expect
before they sell it to the world.

I'm personally fine with using it in production as long as you also copy
all your backups to tape.  That copy will verify your original and will
act as the backup of your backup if the de-dupe software does have a
problem.

5.)what happens if the VTL crashed????

Same thing that happens when a disk array crashes or your tape library
is caught in a fire.  That's why it should never be your only copy of
the data.