Thank you Richard, this sound like the possible solution, I will try it
tomorrow.
But I have now a big doubt. Will each and every filespace use a different
tape?
This will create a unnecessary load in the 3494, and a lot of tapes being
used, normal filespaces that not belong to Oracle DB are small. The 200GB
compacted can even fit in one 3590 cartridge. They would like to divide
evenly the filespaces among the two drives. This is what they used to do
with Legato.
I imagine that if we have two clients in the same machine and distribute the
domains  between them the way we like could be the best solution, but I do
not know how to do that. Can you help?

Thanks
Maria