>  > > 3) does dump accesses data through filesystem, cooked device or raw
> > >    device. i think raw would be the best.
> > 
> > I think it does it via raw device access through /dev/rstN.

Dump starts by getting info about any specified filesystem, using file
metadata for its database of inodes to dump.  Dump does make sure to
handle sparse files correctly.  (Files with holes like some db files.)
Dump uses the fts functions to walk the inode list.

Now you can specify as your dump file /dev/<rawdisk> if it's really
important to you.

Regards,
James