rsync.net's zfs as a service is really great for that, though a bit more expensive than b2 is.
Rsync.net looks great but the storage cost is 5x B2 unfortunately
EDIT: As mentioned below this is for the most expensive (lowest capacity) tier. I’d been comparing for my own home use and so I would be unlikely to exceed 10TB but if you’re looking at higher capacity then maybe the calculus is different.
... for small quantities, yes.
For large quantities, it is 3x, and actually less since there are no charges for ingress/egress.
Further questions/comments over email, please, since this is BBs HN thread and I don't want to butt in.
Without b2 adding anything zfs specific, that should be possible with a regular large file upload if you can deal with each upload part being buffered in a file/memory locally before upload.
But my true dream would be for backblaze to someday offer ZFS as a service.
I want to `zfs send -i my_pool@2020-03-11 | b2zfs recv some_bucket_id`, then be able to view my snapshots and files within in the backblaze web UI, and restore with `b2zfs send -i some_bucket_id/my_pool@2020-03-11 | zfs recv my_pool`.
You can already mount B2 as a FUSE filesystem with something like ExpanDrive, then write ZFS raw file vdevs to the B2 FUSE mount, but it's horrifically slow and probably too janky for any real use.