[arch-general] Installing to RAID .. cannot reboot

[D. R. Evans]

D. R. Evans said the following at 06/20/2012 11:27 AM :
> I have carefully followed the RAID instructions at:
>   https://wiki.archlinux.org/index.php/Software_RAID_and_LVM#RAID_installation
> 
> I have not used LVM, just RAID. I have double-checked what I actually did, and
> believe that I did exactly what the page tells me to do.
> 
> I have two identical drives, which I configured as RAID1.
> 
> At the conclusion of the installation, the instructions say:
> 
> ----
> 
> Once it is complete you can safely reboot your machine:
> 
> # reboot
> 
> ----
> 
> When I try to reboot, I receive the error message:
>   ERROR: device /dev/md0 not found
>   ERROR: unable to find root device /dev/md0
> 
> What do I have to do to get past this error?
> 
>   Doc
> 
> PS I tried to go back to the very beginning and walk through the instructions
> again, but when I do that, when I reach this step:
>   mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sd[cd]3
> I am now informed that /dev/sdc3 is busy or unavailable.
> 

Having spent a chunk of the day on this:

1. I figured out how to avoid the "busy or unavailable" message: one issues
the "mdadm --stop" command. One can then go back to the beginning and
re-create the RAID array(s).

2. So I meticulously started from scratch and, checking every command
carefully, followed the instructions until I reached the point where they tell
me to reboot.

3. On reboot, I am in exactly the same situation as before: the system can't
boot because it cannot find /dev/md0.

I therefore provisionally conclude that of the two possibilities:
  α) I am making a mistake in following the instructions
  β) The instructions contain a fatal error
possibility β seems much the more likely. Most likely something is omitted, I
think.

I (obviously) have no way of knowing where the mistake lies, though, so I'm
completely stuck until someone who understand how all this is supposed to work
can look carefully at the instructions and perhaps spot the error.

After some experimentation with Arch on other (non-RAID) computers, I had
settled on Arch for my main desktop. But that's a RAID system and unless I can
get Arch to install correctly I'm going to have go looking for a different
distro -- which I really, really don't want to have to do, because there's a
lot about Arch that I like  :-(

  Doc

-- 
Web:  http://www.sff.net/people/N7DR

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