I’m out of the loop. What did he do?

Don’t buy lto5. Lto6 is the sweet spot right now.

I can buy lto6 drives on ebay for 250ish. Tapes are like 15-25 bucks each.

You have two things happening at once.

First. There a process that cleans up tmp files according to a configuration. Yours is probably set to clean files older than a day.

https://www.freedesktop.org/software/systemd/man/latest/tmpfiles.d.html for more information

Second, As to the folder. Docker will create a folder with the bind mount’s name if it’s not found. So Docker tries to find your promethius file, doesn’t find it, then creates a folder with that name and mounts it instead.

You should move the files out of tmp. That’ll solve all your problems.