Cannot install grub to RAID1 (md0)
The warning points out the root cause. The new disk that you used for the replacement probably used to have a filesystem on it and grub-setup
is now confused by the metadata that is probably still in there.
So, just wipe out everything at the beginning of the disk up to the first partition. I took the 62
number from the fdisk -l
output. It says that 63
is the start of the first partition, which sounds like there are 62
sectors before it that you can clean out.
dd if=/dev/zero of=/dev/sda bs=512 count=62
Then recreate the partition table:
sfdisk -d /dev/sdb | sfdisk /dev/sda
sfdisk will probably complain about "the kernel may be using the old partition table" but you can ignore the warning since you are not really changing the partition table.
Then you should be able to grub-install /dev/sda
.
Update:
If you are still getting errors, try taking the disk out of the RAID and zeroing out more data from the beginning and the end. Or just zero out the whole disk (dd if=/dev/zero of=/dev/sda
). Then add it back to the RAID as you did before, starting from sfdisk -d /dev/sdb | sfdisk /dev/sda
. And consider switching to metadata format 1.0 as was recommended in a few other places.
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Andrew Answer
Updated on September 18, 2022Comments
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Andrew Answer almost 2 years
I have a RAID1 array on my Ubuntu 12.04 LTS and my /sda HDD has been replaced several days ago. I use this commands to replace:
# go to superuser sudo bash # see RAID state mdadm -Q -D /dev/md0 # State should be "clean, degraded" # remove broken disk from RAID mdadm /dev/md0 --fail /dev/sda1 mdadm /dev/md0 --remove /dev/sda1 # see partitions fdisk -l # shutdown computer shutdown now # physically replace old disk by new # start system again # see partitions fdisk -l # copy partitions from sdb to sda sfdisk -d /dev/sdb | sfdisk /dev/sda # recreate id for sda sfdisk --change-id /dev/sda 1 fd # add sda1 to RAID mdadm /dev/md0 --add /dev/sda1 # see RAID state mdadm -Q -D /dev/md0 # State should be "clean, degraded, recovering" # to see status you can use cat /proc/mdstat
This is the my mdadm output after sync:
/dev/md0: Version : 0.90 Creation Time : Wed Feb 17 16:18:25 2010 Raid Level : raid1 Array Size : 470455360 (448.66 GiB 481.75 GB) Used Dev Size : 470455360 (448.66 GiB 481.75 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Thu Nov 1 15:19:31 2012 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : 92e6ff4e:ed3ab4bf:fee5eb6c:d9b9cb11 Events : 0.11049560 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1
After bebuilding completion "fdisk -l" says what I have not valid partition table /dev/md0. This is my fdisk -l output:
Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00057d19 Device Boot Start End Blocks Id System /dev/sda1 * 63 940910984 470455461 fd Linux raid autodetect /dev/sda2 940910985 976768064 17928540 5 Extended /dev/sda5 940911048 976768064 17928508+ 82 Linux swap / Solaris Disk /dev/sdb: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000667ca Device Boot Start End Blocks Id System /dev/sdb1 * 63 940910984 470455461 fd Linux raid autodetect /dev/sdb2 940910985 976768064 17928540 5 Extended /dev/sdb5 940911048 976768064 17928508+ 82 Linux swap / Solaris Disk /dev/md0: 481.7 GB, 481746288640 bytes 2 heads, 4 sectors/track, 117613840 cylinders, total 940910720 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table
This is my grub install output:
root@answe:~# grub-install /dev/sda /usr/sbin/grub-setup: warn: Attempting to install GRUB to a disk with multiple partition labels or both partition label and filesystem. This is not supported yet.. /usr/sbin/grub-setup: error: embedding is not possible, but this is required for cross-disk install. root@answe:~# grub-install /dev/sdb Installation finished. No error reported.
Some version information:
grub-install (GRUB) 1.99-21ubuntu3.4 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
So
1) "update-grub" find only /sda and /sdb Linux, not /md0
2) "dpkg-reconfigure grub-pc" says "GRUB failed to install the following devices /dev/md0"
I cannot load my system except from /sdb1 (and by hand, not automatically), and in DEGRADED mode...
Anybody can resolve this issue? I have big headache with this.
UPDATE: after wiping out new disk with zeroes, copying partitions with sfdisk update-grub say:
root@answe:~# grub-install /dev/sda error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. Installation finished. No error reported.
Now update-grub generate same errors:
root@answe:~# update-grub error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. Generating grub.cfg ... error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. Found linux image: /boot/vmlinuz-3.2.0-32-generic Found initrd image: /boot/initrd.img-3.2.0-32-generic ... error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. Found memtest86+ image: /boot/memtest86+.bin No volume groups found error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. Found Ubuntu 12.04.1 LTS (12.04) on /dev/sda1 Found Ubuntu 12.04.1 LTS (12.04) on /dev/sdb1 error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. error: found two disks with the index 2 for RAID md0. done
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Andrew Answer over 11 yearsAfter wiping out disk by zeroes I need to add partitions on it. But, immediately after
sfdisk -d /dev/sdb | sfdisk /dev/sda
array rebuild started. If I fail/remove sda from array and try to install grub I got same error. -
Andrew Answer over 11 yearsinstall-grub work fine. Now I have much messages
error: found two disks with the index 2 for RAID md0.