DVD-R as backup medium: growisofs + udftools

["Giuseppe \"Cowo\" Corbelli" <cowo@lugbs.linux.it>]

Hi all
I need an advice, plz.
I'm trying to backup a couple of GBs upon a DVD-R using Plextor PX-810SA, 
Linux 2.6.18.
Backup is incremental and handled by flexbackup tool. Basically this tool 
produces some new files each day (no overwrites) in a directory.

To start I thought about using packet writing / udftools. By reading 
documentation, it states that I have to

dvd+rw-format -force /dev/sr0

for RW media only, so I guess this is not applicable to -R, right?

Then I have to:
<quote>
Write an empty session spanning the whole medium. It seems that
without this step, any attempt to create the UDF filesystem will fail.

DVD-RW: growisofs -Z /dev/sr0=/dev/zero
</quote>

But this does not sound good to me. Wouldn't this just waste my media?

As last step:
mkudffs --udfrev=0x0150 --spartable=2 --media-type=dvd /dev/pktcdvd/0

I tried this command directly and got:
cvsserver:~# mkudffs --udfrev=0x0150 --spartable=2 --media-type=dvd /dev/pktcdvd/0
trying to change type of multiple extents

So it seems I'm really missing something from growisofs.
Does this ring a bell for someone?

Thanks

--
        Giuseppe "Cowo" Corbelli ~\/~ My software: http://cowo.yoda2000.net
-<! Non c'e' niente da dire in proposito. Tutto quello che uno deve fare e'
  colpire i tasti giusti al momento giusto, e lo strumento suona da solo. !>-
                                J.S. Bach