How does deduplication work on encrypted files though? I thought they advertise their personal backup plan to be fully encrypted - this would mean that backblaze shouldn't be able to access / identify the data...
Not sure how the keys are generated (I'm not a backblaze user) but since one apparently has to use their software for backup jobs there might be chance that they also store the keys on their servers for this exact purpose...
This would definitely limit the inconvenience caused by personal users with huge amounts of data - like op with his 80 TB
It would be very easy to test this by backing up a new Windows machine and monitoring outgoing network transfers. If you can backup an entire newly-installed Windows machine and don't see any significant transfers, it is being deduped.
Backblaze has options to supply your own key, but it's an optional feature. I'm gonna guess that over 90% of Backblaze users do not supply their own keys.
