> ideally, there should be some form of asymmetric encryption be used so that decrypting the data requires the possession of one of three off-site YubiKeys with each having a distinct on-key-generated RSA4096 key and the corresponding password
This last one seems to drastically change the design into a place that hasn't really been developed. It would be quite neat, in addition to adding other properties like a compromise of the backed up server couldn't be used to destroy a backup. But assuming your goal is to pragmatically get it done, I would forgo this and accept that your backed up server is going to have full control over the backups.
FWIW I view online/cloud backups as having the strength of being synced often, and therefore up to date in case physical damage happens to the server. For longer term storage I use offsite drives in a safe deposit box, that take care of things like infrastructure being compromised and deliberately deleted along with online backups. For long term data integrity I use ZFS, borg verify, and ad-hoc sha512sums (for things that don't change much, like music collection).
In general keep in mind that your 8TB to backup likely has a power law distribution where your really important filesets are much smaller and can therefore be inexpensively backed up with more copies.
The best pricing I've seen for block devices is Kimsufi (10 USD / 2TB-mo) and buyvm.net (5 USD / 1TB-mo) although I haven't used the latter.
> In general keep in mind that your 8TB to backup likely has a power law distribution where your really important filesets are much smaller and can therefore be inexpensively backed up with more copies.
In my personal experience a simple ignore list can reduce size by an order of magnitude. Things that doesn't make sense to backup like thumbnails, cache files, development dependencies. And smaller is more robust, not only can it be inexpensively backed up with more copies but it can also be synced more frequently with a lower risk of partition and also is quicker to download and restore.
This last one seems to drastically change the design into a place that hasn't really been developed. It would be quite neat, in addition to adding other properties like a compromise of the backed up server couldn't be used to destroy a backup. But assuming your goal is to pragmatically get it done, I would forgo this and accept that your backed up server is going to have full control over the backups.
FWIW I view online/cloud backups as having the strength of being synced often, and therefore up to date in case physical damage happens to the server. For longer term storage I use offsite drives in a safe deposit box, that take care of things like infrastructure being compromised and deliberately deleted along with online backups. For long term data integrity I use ZFS, borg verify, and ad-hoc sha512sums (for things that don't change much, like music collection).
In general keep in mind that your 8TB to backup likely has a power law distribution where your really important filesets are much smaller and can therefore be inexpensively backed up with more copies.
The best pricing I've seen for block devices is Kimsufi (10 USD / 2TB-mo) and buyvm.net (5 USD / 1TB-mo) although I haven't used the latter.