I'm experimenting with running NextCloud (AIO) on a VPS with a B2 bucket as the primary storage. I want to compare performance compared to running it on my home server (esp. when I'm remote) and get an idea of the kinds of costs I'd rack up doing it.

As part of the setup I have configured the built in borg backup but it has this caveat:

Be aware that this solution does not back up files and folders that are mounted into Nextcloud using the external storage app - but you can add further Docker volumes and host paths that you want to back up after the initial backup is done.

The primary storage is external but I'm not using the "external storage" app. So, I have 2 questions.

1. Does it backup object storage if it's primary (my gut says no)?
2. If no, what's a good way to backup the B2 bucket?

I've done some research on this topic and I'm kinda coming up empty. I would normally use restic but restic doesn't work in that direction (B2 -> local backup).

It looks like rclone can be used to mount a B2 bucket. One idea I had was to mount it, read-only, and let AIO/borg backup that path with the container backups.

Has anyone done this before? Any thoughts?