On my system, udev fails to create the /dev/md[0-9] devices for the md driver, thus not allowing me to create a Raid. mknod /dev/md0 c 9 0 should create md0, but then mkraid -V says: cannot determine md version: 6. and exits. I assume that this is udev-related since it used to work on devfs systems and the md driver loads without problems Reproducible: Always Steps to Reproduce: 1. emerge udev raidtools 2. mkraid -V 3. Actual Results: The /dev/md[0-9] devices were missing Expected Results: mkraid should have initialised the raid devices Portage 2.0.51_rc1 (default-x86-1.4, gcc-3.4.1, glibc-2.3.4.20040808-r0, 2.6.7 i686) ================================================================= System uname: 2.6.7 i686 AMD Athlon(tm) XP 2600+ Gentoo Base System version 1.5.3 distcc 2.17 i686-pc-linux-gnu (protocols 1 and 2) (default port 3632) [disabled] ccache version 2.3 [enabled] Autoconf: sys-devel/autoconf-2.59-r4 Automake: sys-devel/automake-1.8.5-r1 Binutils: sys-devel/binutils-2.15.90.0.1.1-r3 Headers: sys-kernel/linux-headers-2.4.22 Libtools: sys-devel/libtool-1.5.2-r5 ACCEPT_KEYWORDS="x86 ~x86" AUTOCLEAN="yes" CFLAGS="-O2 -march=athlon-xp -pipe" CHOST="i686-pc-linux-gnu" COMPILER="" CONFIG_PROTECT="/etc /usr/X11R6/lib/X11/xkb /usr/kde/2/share/config /usr/kde/3.1/share/config /usr/kde/3.2/share/config /usr/kde/3.3/env /usr/kde/3.3/share/config /usr/kde/3.3/shutdown /usr/kde/3/share/config /usr/lib/mozilla/defaults/pref /usr/share/config /usr/share/texmf/dvipdfm/config/ /usr/share/texmf/dvips/config/ /usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/ /usr/share/texmf/xdvi/ /var/qmail/control" CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d" CXXFLAGS="-O2 -march=athlon-xp -pipe" DISTDIR="/usr/portage/distfiles" FEATURES="autoaddcvs ccache sandbox" GENTOO_MIRRORS="ftp://sunsite.informatik.rwth-aachen.de/pub/Linux/gentoo http://gentoo.inode.at/ ftp://gentoo.inode.at/source/" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="" SYNC="rsync://rsync.europe.gentoo.org/gentoo-portage" USE="3dnow X aalib alsa apache2 apm arts avi berkdb bitmap-fonts bonobo cdr crypt cups dga dvd encode esd faad ffmpeg foomaticdb freetype gdbm gif gnome gpm gtk2 gtkhtml imlib java jpeg kde libg++ libwww mikmod motif mozilla mpeg mysql nas ncurses nls oggvorbis opengl oss pam pdflib perl png python qt quicktime readline sdl slang spell ssl tcltk tcpd tetex truetype x86 xml2 xmms xprint xv zlib"
md is not sysfs-aware, MAKEDEV md creates the missing device nodes. The documentation is quite lacking, so it took me some time to track that down.