@olivierlambert that does look interesting. I really need to find a way to make it work over scp/sftp unless you have an in with rsync.net and can get them to add an S3-compatible service
It's not really practical to make a move to an S3 provider at this time; we are 230 TB into rsync.net for a damn good price with no extra charges for data ingress or egress. If I add VM backup, the additional 10+ terabytes are a drop in the bucket of the overall usage.