Hey, I read that message about Freeradius not being able to access /dev/null in a setup where /dev is mounted on an mfs -based filesystem.I'm running similar setup (for years now) - OpenBSD on a USB stick. EVERYTHING is mounted read-only, except /var, /tmp, /dev and /jails, which are mfs - based. Now what I've noticed in particular about /dev is this: for this mfs-based /dev to work I HAD TO leave the initial /dev directory populated with dev files just as it was from the installation. Or else, run MAKEDEV in there -- but make sure it is filled with devices with original permissions etc. When I tried to mount mfs over EMPTY /dev directory, the resulting devices were not accessible. The same proved true about /var. So in order to install packages, I had to remount /usr /var read-write, then install && remount ro. Otherwise it won't work.
Hope that helps With kindest regards, Kostya Berger
