After following the install instructions in gentoo's web site using the minimal livecd 2004.1 method with udev (only), lvm2, and development-sources 2.6.6-rc1 kernel, the resulting system is not functional after rebooting from the hard drive. The file systems under lvm2 control are: \usr, \var, \tmp, \opt. Others not under lvm2 are \boot, swap, and \. All file systems are reiserfs. All instructions for installation including the udev and lvm sections (gentoo website) were used. One exeption to the instructions was that the lvm support was compiled into the kernel and not compiled as a module (as suggested by the install instructions). After rebooting, the kernel is loaded in memory by grub, and error messages related to /dev files and unmounted file systems scrolled fast on the screen; not able to catch them. The prompt appears at the bottom of the display but the system is totally frozen; no keyboard key will cause any response. Booting the system from the livecd and mounting the root file system, does not show the lvm volume groups created during the install in /dev. Reproducible: Always Steps to Reproduce: 1. Install livecd minimal (network install) 2004.1 2. Follow udev and lvm2 install instructions. Keep /boot, and / out of lvm. Use reiserfs. 3. Use the development-sources kernel. Emerge system, and follow configuration steps in the install instructions. 4. Reboot Actual Results: The kernel is loaded in memory by grub, lots of booting messages scrolling on the display (difficult to catch the error messages), until reaching the login prompt. However the system is frozen not allowing login. Many messages related to /dev and unmounted file systems are sent to screen quickly during booting and it is difficult to read them. Expected Results: Boot normally and allow root login. The system is not functional and no emerge can be made. Many messages for help in the gentoo-user list were posted. One reply indicated that the problem seems to be lack of lvm devices that should have been created by udev. Therefore /usr is not mounted since is under lvm control and the system boots with deficiencies.
If the device mapper is compiled as a module during the installation, and when booting in single user mode, the process does not go as far as the normal boot and the following message appears on the screen at the prompt (still frozen display and keyboard): ...top of the display... * Using /etc/modules.autoload.d/kernel-2.c as config: * Loading module dm-mod... * Autoloaded 1 module(s) * Setting up the Logical Volume Manager... /dev/mapper/control: open failed: No such file or directory Is device-mapper driver missing from kernel? * Checking all filesystems... Reiserfs super block in block 16 on 0x301... ...lines omitted... * Mounting local filesystems... mount: special device /dev/vg_fixed/usr does not exist mount: special device /deb/vg_fixed/opt does not exist ....lines omitted... There are as many "mount" complaints are there are file systems under LVM.
Following the installation instuctions with the device mapper enabled in the kernel (2.6.6-rc1 from development-sources) as a module, results in the following warning during installation: Warning: couldn't create /etc/modprobe.conf upon running modules-update after adding dm-mod to the /etc/modules.autoload./kernel-2.6 file.
Hi, I was about to report this as a bug, and I found this here. I believe I have extra info that can help. The problem is that UDEV does not know to create the /dev/mapper/control device node. Without that 'vgchange -a y' fails, and you get no LVM partitions. After some digging around, I discovered that the device-mapper package supplies a script called 'devmap_mknod.sh' which queries /proc and creates a device node with the dynamically assigned major and minor numbers. The comments regarding this script specifically state that it must be used on a non-devfs udev only system. This script needs to be called early in the boot process. I hacked my /sbin/rc to call it as part of the UDEV setup. That seems to have worked and solved my problem. Hope that helps, -Mark
this isnt the way it should be done. this happens because you compile device mapper as module, and when you load, it doesent get to create the device quick enough. building device mapper in, makes the module be created faster, and the checkfs init script which enables logical volume manager will run vgchange properly.
I had to add KERNEL="device-mapper", NAME="mapper/control" to /etc/udev/rules.d/50-udev.rules to make it work. that should be in there by default
Should now be fixed with the latest version of udev.
