Re: RAID1 all bootable

[Bob Proulx <bob@proulx.com>]

Francesco Pietra wrote:
> Bob Proulx wrote:
> > Francesco Pietra wrote:
> >> Thanks so much for this manual. Unfortunately, I have no more the
> >> initial situation (one HD replaced) because I was hurried by an editor
> >> to provide computational data from my CUDA server. I did not want to
> >> run the server before all my data were backed up. Therefore I did a
> >> fresh amd64 wheezy install on both disks, the old one and the newly
> >> replaced. The installation ended with:
> >
> > Sad to see that you have given up already and destroyed your data.
> 
> I had all my data on another raid1 machine. Following the new install,
> all data were scp transferred. All my machine are on a router, with
> passwordless scp. Which is also used to contact external server for
> computational work.

Oh!  Okay.  I thought you had installed over it.  I see now that you
installed upon a different system and copied over to it.  Very good.

> Following a seemingly correct installation, with grub installed
> 'grub-install /dev/sda' and 'update grub'
> 
> command
> 
>  grub-install /dev/sdb
> 
> led to a system that did no more boot. I can't see what was wrong with
> the installation. I have now the same situation (install from the
> wheezy installer). If you suggest what to check, I'll do that.

I can't think of any reason for that to fail.  It works for me.  (I do
always set up a separate /boot but a /boot that is also on RAID1.  But
it eliminates the LVM interaction.  Which previously was not supported
but now as I understand it is fully supported.)  I am sorry but I
cannot think of anything to suggest.

I always found grub 1 easier to debug than grub 2.  With grub 1 it was
possible to do something like this:

Verify that the grub files are on both disks:

  grub>find /grub/stage1
  (hd0,0)
  (hd1,0)

Install grub onto the second disk:

  grub> device (hd0) /dev/sdb
  grub> root (hd0,0)
  grub> setup (hd0)
  grub> quit

But now with grub 2 there is only the install script:

  grub-install /dev/sdb

I can only suggest that if you have the resources set up a "victim"
machine and do test installations and then try different combinations
in order to learn enough about the problem in order to debug it.

> Thanks a lot for your generous help. I (we) learned a lot from you.

Happy to help.  I only wish it could have been more useful.

Bob