I tried to upgrade my cnMaestro On-premise from version 1.6.3-r19 to 2.1.0-r22, but i have problems to importe the data.
The file it's uploaded correcly to cnMaestro and late in restoring proccess it's freez at 25% and doesn't do any.
We have more than 4000 devices connected and it's impossible adopt all and re-create the templates, the systems ...etc
I had the same problem as you but my backup was from 1.6.3-r39. This is what worked for me.
1. copy backup .tar.gz file to cnmaestro 2.1 server
2. ungzip backup file > gzip -d cnmaestro-export_cnmaestr_20190228T184052382875.tar.gz
3. Run import command > sudo cnmaestro-import cnmaestro-export_cnmaestr_20190228T184052382875.tar
4. Wait for progress (get coffee, bio break)
5. Wait for the reboot.
6 examine results.
I have the same problem. Also, I am not Linux expert, could you please elaborate how to copy file to cnMaestro server?
EDIT: Looks like I am now almost Linux expert. I fugured it out. Thanks anyway.