Hi Francesco,
I was under the impression your grub configuration was correct and the only thing wrong was not having it installed on that one HDD. Of course your grub configuration should point to the correct root.
In my little (easy) setup I have my main partition, boot partition and swap partition in raid-1. The update-grub command was able to create the correct entries for this configuration in my grub.cfg all by itself.
If grub is sending you to the rescue prompt it means something it wrong with your grub configuration, so you'll have to fix that and install grub again.
With kind regards,
Simon
Hi Lennart, Hi Simon
A proper understanding of mdadm is required. Hurrying with focus on
codes for biochemical applications has brought me into a mess.
Relying of all my data, and special compiled programs, present on
another raid1 amd64 wheezy, I carried out a reinstall of amd64 wheezy
on the machine with new HD. mdo (boot, ext20, md1 (LVM, home, usr,
etc). GRUB was installed on /dev/sda
Then the command
grub-install /dev/sdb
with reported installation compete. No errors reported.
On rebooting, GRUB was no more found, entering in
grub rescue >
which should also be known accurately, because prefix/root/ are now wrong.
The only care I exerted, was not to work with the machine where I have
my data, until the damaged machine is in order again. At any event,
how to install safely GRUB on both disks of a RAID1 is a must.
Thanks for your kind advice.
francesco pietra
As to mdadm,
On Sat, Mar 2, 2013 at 7:05 AM, Simon Vos <simonvos@gmail.com> wrote:
> Have you assembled you raid devices again (mdadm --assemble /dev/mdX
> /dev/sdX)?
>
> That should still work with the disk that was used for your RAID-1, when
> that's done you can mount your disk, chroot into it and run grub-install
> /dev/sda (and grub-install /dev/sdb, so you won't have this problem in the
> future ;-)).
>
>
> On 2 March 2013 11:10, Francesco Pietra <chiendarret@gmail.com> wrote:
>>
>> A further piece on information. With knoppix 7.0, the procedure for
>> examining mdadm arrives at
>>
>> cat /proc/partitions
>> sda
>> sdb
>>
>> RAID1 (md0 md1) is not seen. I assume that this is the way Knoppix
>> behaves in this situation.
>>
>> Thanks
>> francesco pietra
>>
>>
>> ---------- Forwarded message ----------
>> From: Francesco Pietra <chiendarret@gmail.com>
>> Date: Sat, Mar 2, 2013 at 10:11 AM
>> Subject: Re: RAID1 all bootable
>> To: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>, amd64 Debian
>> <debian-amd64@lists.debian.org>, debian-users
>> <debian-user@lists.debian.org>
>>
>>
>> Is this recipe devised for installing grub on both sda and sda with an
>> undamaged RAID1?
>>
>> In my case, with the sda that contained grub loader replaced by a new
>> disk, the rescue mode (using the same CD installer for amd64 wheezy)
>> did not find any partition. Inverting the SATA cables, same result.
>>
>> In both cases (I mean position of SATA cables) I went to the shell in
>> the installer environment:
>>
>> #fisk /dev/sda (or sdb)
>> device contains neither a valid DOS partition table, nor Sun, etc
>> (expected for a raid)
>>
>> #dmesg |grep -i sd
>> sda (and sbb): unknown partition table (expected for a raid), however
>> md: raid0
>> md: raid1
>> were identified, along with rai4, 5, 6 etc (unfortunately "| less"
>> does not work to see the whole message).
>>
>> Am I using the Rescue Mode improperly? I was unable to dig into the HD
>> that contains md0 (booth loader, EXT2) and md1 ( LVM partitions home
>> tmp usr opt var swap EXT3)
>>
>> Thanks a lot for your kind advice
>>
>> francesco pietra
>>
>>
>>
>> On Fri, Mar 1, 2013 at 10:35 PM, Lennart Sorensen
>> <lsorense@csclub.uwaterloo.ca> wrote:
>> > On Fri, Mar 01, 2013 at 08:20:09PM +0100, Francesco Pietra wrote:
>> >> Hi:
>> >> With a raid1 amd64 wheezy, one of the two HDs got broken.
>> >> Unfortunately, I had added grub to sda only, which is just the one
>> >> broken. So that, when it is replaced with a fresh HD, the OS is not
>> >> found. Inverting the SATA cables of course does not help (Operative
>> >> System Not Found). In a previous similar circumstance, I was lucky
>> >> that the broken HD was the one without gru.
>> >>
>> >> Is any way to recover? perhaps through Knoppix? I know how to look
>> >> into undamaged RAID1 with Knoppix.
>> >>
>> >> Also, when making a fresh RAID1 from scratch, where to find a Debian
>> >> description of how to make both sda and sdb bootable? (which should
>> >> be included by default, in my opinion)
>> >
>> > You can boot the install disk in rescue mode, select the root partition
>> > to chroot into, then run grub-install from there.
>> >
>> > When grub asks where to install, you should configure it for both sda
>> > and sdb. I think 'dpkg-reconfigure grub-pc' is where that is selected.
>> > Might need it to use -plow to asks all levels of questions. Not sure.
>> >
>> > --
>> > Len Sorensen
>>
>>
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