I'm posting this as a feature because I don't believe it's currently supported.
I'm trying to use the union of several remotes as a target for my backup.
it would be really useful to have a redundancy feature in the union remote to be more robust to failures, e.g. one of the underlying remotes is discontinued or dies.
rclone could upload N copies of the same file, as opposed to a single one, just making sure that they end up in different underlying remotes of the same union.
then the "first found" policy of the union remote would take care of reading.
what do you think? I believe it would be useful.