[gosub100]

I have about that much data and LTO-6 (2.5tb per tape), and it's a huge PITA. I'm probably doing it wrong, but this is what worked for me: making an ext4 filesystem as a file, exactly 2500gb in size, formatting it, and stuffing it with data until there is < 5 gb free. take the checksum and manifest of that file, and write it to tape (takes 4 hrs without verify, plus another 1-3 hrs (can't remember now, its faster) to verify. repeat until your 40tb is done.

I know you can use ZFS snapshots but I'm not experienced enough to trust that I could make a 20-40tb snapshot without screwing something up. Plus it's all video files so I can roughly keep track of what's what and I can ignore the stupid LTO compression.

It takes days, its noisy, and very tedious. But thats #hoarderLyfe lol