That's a strange choice, HTTPS would incur quite a bit of overhead for something that is essentially a (large) drive at the end of a network cable used internal

That's a strange choice, HTTPS would incur quite a bit of overhead for something that is essentially a (large) drive at the end of a network cable used internally only. Why the encryption ? To help prevent a network compromise from resulting in storage management compromise? Just because something is internal doesn't mean it's safe. Once a host/network segment is compromised, you don't want it to be easy to jump to the next. Otherwise, you've built M&M security. Hard candy shell on the outside, soft gooey chocolate insides. Mmm.