[martianrock]

Originally Posted by theducks

https://manual.calibre-ebook.com/gen...re-server.html
I believe You can STILL use the CLI to start multiple instances if you specify With Library.
I used to do the way back around Calibre 2 where server (instance) could only do 1 Library

There's no --with-library option but I did provide distinct path to different libraries for each instance. And yet I still got an error on startup of one of the instances saying another instance is running. No idea why, I suspect this error is a bug.

I got around that by having Environment="CALIBRE_NO_SI_DANGER_DANGER=Y" in systemd config for each since I am pretty sure that separate instances talk to separate libraries. That and one of them is intended as read-only. So I hope actual danger is not that big, though it would be nice if I didn't have to use this override.