For my archival use (the reason why I got into this in the first place) I do not encrypt nor compress the data going to tape. For server/desktop backups. they are compressed and encrypted.
Just to note that tape drives have built-in compression that generally is done transparently in the background. So while using something like zstd (per the article) may get more bits on a given tape, there is some compression that one gets "for free" without doing anything at all.
* https://en.wikipedia.org/wiki/Linear_Tape-Open#Optional_tech...
* https://en.wikipedia.org/wiki/Magnetic_tape_data_storage#Dat...
> Drives above LTO-4 have built-in hardware encryption, however I would steer away from using it and instead just encrypt data yourself (possibly with the tool I helped make called age!). Like most things, you should also consider compressing your data before encrypting and writing it to tape. LTO tape capacities are often quoted in their “compressed capacity” which is a little cheeky since it assumes basically over a 50% compression ratio, this is not at all likely to be true if you are writing video or other lossy mediums like images etc to the tape. I generally run my data through zstd to compress and then age to encrypt. Zstd and age are quite fast and I’ve not found them to impede performance noticeably.
If someone is not familiar with tape drives, I think it would be easy not to realize that the compression is built into drives like the explicitly called out "built-in hardware encryption".
I used to work for a government agency. We ran backup tapes that rotated out through a degaussing machine that spun them around for like 10 minutes to wipe them. It’s not common to have, but it’s definitely easy.
So, it would take a very dedicated nerd indeed.