Unable to launch rsync daemon on backup host

Thanks gayle for the reply and the solution, we had to follow the same process to get the backups working. Did your issue come back the next time the backups ran?

No, the backups ran fine after that. The only other issue that we came accross was that the backups were stored in a different way to before the upgrade, so instead of storing one copy of the database (and overwriting the previous copy), plus snapshots, we were actually trying to store 2 copies, one from before the upgrade and one from after, which caused us to run out of space on our backup disk. So we had to delete the old copy, and now everything seems to be fine.

Yes, we had to overwrite the backups as well.

I can confirm the same issues (and solutions) as above. 

Constantly impressed at just how awful this software is. 

Another thing to try: check that the uid and gids for both dbadmin and the verticadba groups are consistent between the database nodes and the backup hosts. An inconsistency in the verticadba group also gave us this error.