/ is mounted read-only, so you can't make directories on it the entire point of having the /var/run tmpfs is to have a writable area before we are able to mount the root filesystem writable
chicken and egg otherwise -- missing /var/run in root partition fails many services https://launchpad.net/bugs/51452 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
