I usually use 7z as well… mostly because of the higher compression ratio. I resend in zip if I get complaints, but if it’s a large file that barely fits in size on whatever hosting service I decide to share the file on, I just tell them to install 7zip or any other archiver that can open 7z archives. If they don’t how to do it, hey I also offer remote IT assistance 🤷.
Might be a SAS driver issue. Have you checked if the drives show up on a live distro, something more current, like let’s say Void or anything that has a 6.x kernel?
I’ve had issues like this with older Marvel SCSI controllers, some of them don’t have open source drivers for Linux, and the ones provided by the manufacturer (if there are any) are so old that you’d have to be runnig kernel 2.x in order for them to work. I just gave up in the end, disabled the SCSI controller in BIOS and just used the rigs on IDE/SATA.