You don't say what version Oracle you are using. Compression was added and does a great job of compressing your dumpfile. Have you tried that to see how big the dumpfile would be?
When you say that " the transfert by network is too slow for our production requirements" are you talking about how long it would take for this to go over the network? What did you try? Did you try just file over the network? There is also network import, have you tried that? There isn't much information on what you have tried to see if there are some options to explore.
Hi, thanks for your response. The version is 22.214.171.124. We didn't try to compress the dump because we don't have access to the source database (not managed by us). Finally the dump is directly generated in a nfs share created on destination which is acceptable for us. Besides that we managed to import data before the final outage which reduces the whole operation at 7h.