I've put together a new How-To for NFS-RAMBOOT - a boot script hack to load the entire OS partition into RAM. The result is like a very fast SSD.

In this version, the OS tarball is loaded over the network via an nfs share. This can actually be faster than a local hard drive, if the nfs share is on an SSD or faster hard drive. Also, it can be convenient from a power/noise perspective to have just a single hard drive in a file server provide the OS tarballs for multiple computers.

http://www.linuxquestions.org/questi...stretch-37467/

This how-to is for Debian 9 Stretch, but the same basic techniques should work for any distribution. The hack I use goes back to before systemd; it works both with or without systemd.