On Sat, 2007-05-12 at 22:16 +0100, Sam Morris wrote: > On Wed, 2007-05-09 at 18:13 +0200, Robert Millan wrote: > > I'm forwarding you a bug report from Debian. It seems that the grub-probe > > -t partmap feature I just added doesn't play nice with RAID. Unfortunately, > > I have no idea how software RAID is implemented. Is it okay to just exit > > succesfuly and install core.img without any partmap module? > > Hi Robert, > > I altered grub-install to not fail if the partmap module could not be > determined, and then rebooted. I was put straight into rescue mode, and > 'ls' only showed (hd0) (hd1) (hd2)... so I guess at least 'pc' is > necessary for Linux software RAID setups. > > After editing the script to fall back to 'pc' if partmap_module could > not be determined, I rebooted again. This time I got the menu, however > it had (what appeared to be) only a single, blank entry. Hitting enter > or pressing 'e' locked up the system. I could press 'c' to get to a > command prompt, however. > > Upon doing so, I did 'ls' and could see the individual partitions insead > of just the disk devices. However I didn't know what else to do, so I > booted back up with grub 1 and sent this message.
I experimented some more. At the command prompt I entered 'insmod raid' and got the message 'error: out of disk'. I assume that is because the partition containing my RAID1 array extends past the area readably by BIOS functions. However, I was able to ignore the message: if I then ran 'ls', '(md0)' showed up in the list of devices just fine! Next I did 'source (md0)/boot/grub.cfg' and was brought to the working GRUB menu. I guess that is because /boot and its contents are within the area of the disk readable by the BIOS functions. I had to do one more thing to boot up correctly: edit the command line. It had 'root=md0' but it needed 'root=/dev/md0'. It appears that 'grub-probe -t device /boot/grub' outputs 'md0' when it should be outputting '/dev/md0' (just as it outputs e.g., '/dev/hde1' instead of 'hde1' for 'grub-probe -t device /mnt'). Shall I file a separate bug for that? BTW, it would be convenient if I could override the detected GRUB_DEVICE by editing /etc/default/grub; however it seems that update-grub ignores the environment variable and always overrides it with the value output by grub-probe. It might be useful to allow the user to specify the grub device manually in this manner. So anyway, having booted up, I edited grub-install again, to set partmap_module='pc raid', and re-ran it. However when booting up this time, I was straight back to the recovery console. It appears that I can only boot up if I insert the 'raid' module manually at the regular GRUB prompt. -- Sam Morris http://robots.org.uk/ PGP key id 1024D/5EA01078 3412 EA18 1277 354B 991B C869 B219 7FDB 5EA0 1078
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