Install grub2 to /dev/md126 fails

Install grub2 to /dev/md126 fails

[jlcenter]

Hi,

I've been trying to install Ubuntu 11.10 on a mdadm imsm raid1 array, but it fails installing grub.  I had to chroot /target to install mdadm from the distribution.  I've also upgraded to the latest version of mdadm, hoping this would fix the problem.  This is the error I'm getting:

root@ubuntu:/# grub-install --recheck /dev/md/V1
/usr/sbin/grub-probe: error: no such disk.
Auto-detection of a filesystem of /dev/md126p3 failed.
Try with --recheck.
If the problem persists please report this together with the output of "/usr/sbin/grub-probe --device-map="/boot/grub/device.map" --target=fs -v /boot/grub" to <bug-grub@gnu.org>

Here's how mdadm sees my config:

root@ubuntu:/dev# mdadm --examine --scan
ARRAY metadata=imsm UUID=92ae2913:95d651ca:62154f33:7069b04c
ARRAY /dev/md/V1 container=92ae2913:95d651ca:62154f33:7069b04c member=0 UUID=71b12777:c6a51a84:5b0f1d11:0bd6e497

I also tried with several variations of /dev/md126, etc., but always with the same result.  I also tried to install directly to one of the disks in the array, but this didn't work, either.  When I ran grub-probe, I got the following error:

/usr/sbin/grub-probe: info: opening mduuid/71b12777c6a51a845b0f1d110bd6e497,3.
/usr/sbin/grub-probe: error: no such disk.

What could be causing this problem?  How do I fix it?  Please let me know if I need to supply more information to troubleshoot this problem.

Thanks.

    -John

Re: Install grub2 to /dev/md126 fails

[NeilBrown]

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On Sat, 31 Dec 2011 03:59:13 +0000 (UTC) jlcenter@comcast.net wrote:

> Hi,
> 
> I've been trying to install Ubuntu 11.10 on a mdadm imsm raid1 array, but it fails installing grub.  I had to chroot /target to install mdadm from the distribution.  I've also upgraded to the latest version of mdadm, hoping this would fix the problem.  This is the error I'm getting:
> 
> root@ubuntu:/# grub-install --recheck /dev/md/V1
> /usr/sbin/grub-probe: error: no such disk.
> Auto-detection of a filesystem of /dev/md126p3 failed.
> Try with --recheck.
> If the problem persists please report this together with the output of "/usr/sbin/grub-probe --device-map="/boot/grub/device.map" --target=fs -v /boot/grub" to <bug-grub@gnu.org>
> 
> Here's how mdadm sees my config:
> 
> root@ubuntu:/dev# mdadm --examine --scan
> ARRAY metadata=imsm UUID=92ae2913:95d651ca:62154f33:7069b04c
> ARRAY /dev/md/V1 container=92ae2913:95d651ca:62154f33:7069b04c member=0 UUID=71b12777:c6a51a84:5b0f1d11:0bd6e497
> 
> I also tried with several variations of /dev/md126, etc., but always with the same result.  I also tried to install directly to one of the disks in the array, but this didn't work, either.  When I ran grub-probe, I got the following error:
> 
> /usr/sbin/grub-probe: info: opening mduuid/71b12777c6a51a845b0f1d110bd6e497,3.
> /usr/sbin/grub-probe: error: no such disk.
> 
> What could be causing this problem?  How do I fix it?  Please let me know if I need to supply more information to troubleshoot this problem.
> 

Sounds like a problem with 'grub'.  I suggest you find a list for discussing
that tool.

Feel free to keep linux-raid on 'cc' as the outcome may be interesting for us
too.

Thanks,
NeilBrown

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Re: Install grub2 to /dev/md126 fails

[Jes Sorensen]

On 12/31/11 04:59, jlcenter@comcast.net wrote:
> Hi,
> 
> I've been trying to install Ubuntu 11.10 on a mdadm imsm raid1 array, but it fails installing grub.  I had to chroot /target to install mdadm from the distribution.  I've also upgraded to the latest version of mdadm, hoping this would fix the problem.  This is the error I'm getting:
> 
> root@ubuntu:/# grub-install --recheck /dev/md/V1
> /usr/sbin/grub-probe: error: no such disk.
> Auto-detection of a filesystem of /dev/md126p3 failed.
> Try with --recheck.
> If the problem persists please report this together with the output of "/usr/sbin/grub-probe --device-map="/boot/grub/device.map" --target=fs -v /boot/grub" to <bug-grub@gnu.org>
> 
> Here's how mdadm sees my config:
> 
> root@ubuntu:/dev# mdadm --examine --scan
> ARRAY metadata=imsm UUID=92ae2913:95d651ca:62154f33:7069b04c
> ARRAY /dev/md/V1 container=92ae2913:95d651ca:62154f33:7069b04c member=0 UUID=71b12777:c6a51a84:5b0f1d11:0bd6e497
> 
> I also tried with several variations of /dev/md126, etc., but always with the same result.  I also tried to install directly to one of the disks in the array, but this didn't work, either.  When I ran grub-probe, I got the following error:
> 
> /usr/sbin/grub-probe: info: opening mduuid/71b12777c6a51a845b0f1d110bd6e497,3.
> /usr/sbin/grub-probe: error: no such disk.
> 
> What could be causing this problem?  How do I fix it?  Please let me know if I need to supply more information to troubleshoot this problem.

Did your raid device(s) get added to /boot/grub2/device.map correctly?
If not, does it install properly if you add the devices there manually?

I've had a pile of problems with grub2 on Fedora, including something
like this.

Cheers,
Jes

Re: Install grub2 to /dev/md126 fails

[jlcenter]

From: "Jes Sorensen" <Jes.Sorensen@redhat.com>

Did your raid device(s) get added to /boot/grub2/device.map correctly?
If not, does it install properly if you add the devices there manually?

I've had a pile of problems with grub2 on Fedora, including something
like this.


Hi Jes,

When I tried to create the device.map file, it only added the individual disks, not the raid devices.  I then tried to add them by hand, but I kept getting an error whenever it hit the raid1 volume.  What did you see & how did you resolve it?

Thanks.

    -John

Re: Install grub2 to /dev/md126 fails

[Jérôme Poulin]

I'm pretty sure this is the same problem I had with GRUB which
probably wasn't fixed, GRUB detects the whole device instead of a
single partition with metadata at the end of the disk because of wrong
detection order. See this thread:
http://lists.gnu.org/archive/html/grub-devel/2011-01/msg00057.html

On Tue, Jan 3, 2012 at 8:35 PM, <jlcenter@comcast.net> wrote:
>
> From: "Jes Sorensen" <Jes.Sorensen@redhat.com>
>
> Did your raid device(s) get added to /boot/grub2/device.map correctly?
> If not, does it install properly if you add the devices there manually?
>
> I've had a pile of problems with grub2 on Fedora, including something
> like this.
>
>
> Hi Jes,
>
> When I tried to create the device.map file, it only added the individual disks, not the raid devices.  I then tried to add them by hand, but I kept getting an error whenever it hit the raid1 volume.  What did you see & how did you resolve it?
>
> Thanks.
>
>    -John
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Re: Install grub2 to /dev/md126 fails

[jlcenter]

Hi,

I'm going to try again to build the raid1 array, but I was wondering if the GPT partitions should be created first on the physical disks, then create & assemble the array?  Or, if the array should be created & assembled, then partition the array?  I'm raiding the whole disk(s), not partitions.  My feeling is that the array should be built first, then partitioned, but I have been known to be wrong... :-)  Also, is there any special order to the partitions, i.e., does the bios boot partition have to be the first partition on the array?

Thanks.

    -John

Re: Install grub2 to /dev/md126 fails

[jlcenter]

Hi,

I'm going to try again to build the raid1 array, but I was wondering if the GPT partitions should be created first on the physical disks, then create & assemble the array?  Or, if the array should be created & assembled, then partition the array?  I'm raiding the whole disk(s), not partitions.  Reading the wiki, I get the impression the first way is preferable, but most of the descriptions I've read on-line suggest doing the latter.   Also, for mdadm with GPT partitions, is there any preferred order to the partitions, i.e., does the bios boot partition have to be the first partition on the array?

Thanks.

    -John

Re: Install grub2 to /dev/md126 fails

[John Robinson]

On 06/01/2012 15:32, jlcenter@comcast.net wrote:
> Hi,
>
> I'm going to try again to build the raid1 array, but I was wondering
> if the GPT partitions should be created first on the physical disks,
> then create&  assemble the array?  Or, if the array should be
> created&  assembled, then partition the array?  I'm raiding the whole
> disk(s), not partitions.  Reading the wiki, I get the impression the
> first way is preferable, but most of the descriptions I've read
> on-line suggest doing the latter.   Also, for mdadm with GPT
> partitions, is there any preferred order to the partitions, i.e.,
> does the bios boot partition have to be the first partition on the
> array?

If my understanding is correct, you want an IMSM array that can be 
booted by a uEFI BIOS? In which case, I think you need an array over the 
whole disks (which might give you a /dev/md127 for a container, and 
/dev/md126 for the data), GPT partition table over that, first partition 
a GPT boot partition (so you will be installing GRUB2 to /dev/md126p1 - 
this is NOT a filesystem partition), and then whatever you want after 
that, e.g. to keep it simple a /dev/md126p2 for swap and /dev/md126p3 
for your filesystem.

If you don't have a uEFI BIOS, it gets more complicated; you will need a 
hybrid MBR with a traditional boot sector and at least the GPT boot 
partition exposed :-(

Caveat: I've read a lot but I haven't actually done this, so I may be 
talking rubbish...

Cheers,

John.