On Fri, Oct 08, 2010 at 10:30:23AM -0500, Chris Weber wrote: > >> Now I can boot from /dev/sdd, but the kernel panics because it can't > >> mount the root filesystem (/dev/md0p2). Entries in /etc/fstab on md0p2 > >> are correct. I take it the md-devices aren't up/accessible in time. > >> > >> Any idea what's missing? Like there's no RAID support in grub? > >> > >> _______________________________________________ > >> Help-grub mailing list > >> [email protected] > >> http://lists.gnu.org/mailman/listinfo/help-grub > >> > > > > Have you made a new initrd that has md and/or raid support? I ran > > I'm guessing that you might need an extra module for raid support and > maybe some extra lines in init, but maybe this will help get you > started.
All that's needed for booting is compiled into the kernel, I'm not using initrd at all. Not using initrd makes things a lot easier ... The question probably is why the kernel doesn't seem to know about the RAID devices. If I understand things correctly, those might be started only after the root partition has been mounted. If that is true, having the root partition on a software RAID device would be generally impossible --- unless grub (or whatever else) does something to make them available to the kernel so that the root partition can be mounted. Now I can speculate that when having a root partition on a software RAID device that is not partitioned, the boot process is cheating in that the kernel first mounts the root partition from one of the physical disks the RAID device is made from and later somehow changes to the actual RAID device. That might explain why it's not possible to boot from a RAID5. Does anyone know how this works? There have been Debian installers that asked the user who created RAID devices during the installation which devices would have to be brought up at boot time. Recent installers don't seem to ask that anymore. This leads to wondering why the partition type "raid autodetect" is deprecated and wheather it is nevertheless required when the root partition is on a RAID device or not. In any case, before the root partition is mounted, /etc/mdadm/mdadm.conf cannot be read. So how can the software RAID devices be brought up before the root partition is mounted? How does one tell grub to bring up the software RAID devices? It seems that the modules "raid" and "mdraid" are required, and I've put them into the grub.cnf. Perhaps I also need to put some information into grub.cnf about what physical devices/partitions to use to bring up the RAID devices. But how do I do that? _______________________________________________ Help-grub mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-grub
