Anything transient writable must be in memfs/tmpfs/how it is mamre im your OS, of course. Logs to log server, if system needs non-volatile writable storage — N

Anything transient writable must be in memfs/tmpfs/how it is mamre im your OS, of course. Logs to log server, if system needs non-volatile writable storage — NFS or second storage device, depending on requirements. Of course, it is too much hassle for single such system (but I started to use it from very beginning out of curiosity) but uf you have many single-task small devices it is very convenient.