Problem with grub-install on Dell Vostro pc, after a restore

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Problem with grub-install on Dell Vostro pc, after a restore

Postby ole_thor » 2020-01-23 11:19

20200123 20:15 ; the problem has been resolved. see edit in green italics below for missing code.
I couldn't boot from the disk after restore.
The system has 3 disks, 240GB SSD (sda), 320GB HDD (sdb), 320GB HDD (sdc).
I want to be able to boot debian buster from any 1 of the 3 disks by selecting the boot disk from the Bios.
The system used to have win7 installed with similar operation to below (without grub) and it worked from each disk.
I am trying to migrate from windows to Debian Buster.

I have installed buster on each of the disks from a live installation dvd (10.2) with 4 primary msdos partitions.

    /boot ........... ext2 512MB
    / .................. ext4 16GB
    swap .......... 8GB
    /home ......... ext4 rest of disk
I am able to boot from any of the 3 disks and get into the OS.

To test backup and recovery, I backup from sdb and recover to sdc.
The backup process is as follows:
    Boot from sda
    save the partition information with sfdisk --dump /dev/sdb > sdb.dump
    save the MBR information (and partition info) with dd if=/dev/sdb of=backup-sdb.mbr bs=512 count=1
    mount the partitions to /disks/Bkp-Boot /disks/Bkp-Root /disks/Bkp-Home
    backup sdb (using tar for /boot, /, /home to separate files)
      tar -C /disks/Bkp-Boot -cvzf sdb-Boot_20200122.tar.gz --one-file-system ./ > sdb-Boot_20200122.txt 2>&1
      tar -C /disks/Bkp-Root -cvzf sdb-Root_20200122.tar.gz --one-file-system ./ > sdb-Root_20200122.txt 2>&1
      tar -C /disks/Bkp-Home -cvzf sdb-Home_20200122.tar.gz --one-file-system ./ > sdb-Home_20200122.txt 2>&1
To ensure that the restore simulates a replacement of the disk, I use gparted to create a gpt partition table on sdc.
The restore process (from backup of sdb to "new" disk sdc) is as follows:
    boot from sda
    restore the MBR and partition info with "dd if=backup-sdb.mbr of=/dev/sdc bs=512 count=1".
      with or without the previous step, yields the same result.
    initialize sdc partitions with sfdisk /dev/sdc < sdb.dump
    verify that the partitions are created correctly with sfdisk -l /dev/sdc
    initialize the file systems and swap
      mkfs.ext2 -L Bkp-Boot /dev/sdc1
      mkfs.ext4 -L Bkp-Root /dev/sdc2
      mkswap -L Bkp-Swap /dev/sdc3
      mkfs.ext4 -L Bkp-Home /dev/sdc4
    mount the partitions to /disks/Bkp-Boot /disks/Bkp-Root /disks/Bkp-Home
    verify that the partitions are mounted correctly with mount -l | grep sdc
    restore /boot, /, /home to sdc
      tar -xvf sdb-Boot_20200122.tar.gz -C /disks/Bkp-Boot --numeric-owner > sdc-Boot_Restore_20200122.txt 2>&1
      tar -xvf sdb-Root_20200122.tar.gz -C /disks/Bkp-Root --numeric-owner > sdc-Root_Restore_20200122.txt 2>&1
      tar -xvf sdb-Home_20200122.tar.gz -C /disks/Bkp-Home --numeric-owner > sdc-Home_Restore_20200122.txt 2>&1
    fix /disks/Bkp-Root/etc/fstab so that it has all the correct UUIDs
    execute "grub-install /dev/sdc" reports no errors. This is not required
    mount /dev/sdc1 /disks/Bkp-Root/boot
    for i in /dev /dev/pts /proc /sys /run; do mount -B $i /disks/Bkp-Root$i; done
    chroot /disks/Bkp-Root
    grub-install /dev/sdc
    update-grub
    ctrl-d to exit chroot


reboot system and select "boot from sdc" in bios.
The system now boots to /dev/sdc.

these lines are no longer relevant:
The system boots but goes to /dev/sdb instead of /dev/sdc.
I used kdiff3 to compare the /boot/grub/grub.cfg on sdb and sdc and they are identical, indicating that the grub-install did not change the grub info on sdc.

I arrived at this process after several days of googling and trying different suggestions and trying to understand the grub information, but I have run out of ideas on how to resolve this.

Any thoughts on what I need to do to be able to boot from sdc at this point?
thanks for any assistance.
Last edited by ole_thor on 2020-01-24 00:44, edited 1 time in total.
ole_thor
 
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Re: Problem with grub-install on Dell Vostro pc, after a res

Postby Head_on_a_Stick » 2020-01-23 18:28

ole_thor wrote:I used kdiff3 to compare the /boot/grub/grub.cfg on sdb and sdc and they are identical, indicating that the grub-install did not change the grub info on sdc

Why do you think the grub-install command will change grub.cfg? See https://wiki.debian.org/Grub#Configuring_GRUB_v2
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Re: Problem with grub-install on Dell Vostro pc, after a res

Postby ole_thor » 2020-01-23 20:08

head_on_a_stick:
I was expecting that the grub.cfg file would have to be changed to use the correct UUID for the boot device.

I did find somewhere that I needed to do a chroot to the target before I do the grub-install and then I have to do upgrade-grub to change the grub.cfg that I was looking for. I added that to the process, however, now I am getting a bunch of failures on the boot and I am looking into those.
failed to start hostname service
failed to start daily apt download activities
failed to start daily apt upgrade and clean activities
... and a bunch of other ones that went off the screen.

I will update the post when I am done investigating why these failures occurred.
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Re: Problem with grub-install on Dell Vostro pc, after a res

Postby ole_thor » 2020-01-24 00:28

I have resolved the problems.
1- original problem (won't boot to correct disk) was resolved by adding this code after the restore and then the system will boot from the correct disk:
    mount /dev/sdc1 /disks/Bkp-Root/boot
    for i in /dev /dev/pts /proc /sys /run; do mount -B $i /disks/Bkp-Root$i; done
    chroot /disks/Bkp-Root
    grub-install /dev/sdc
    update-grub
2 - problem with failed processes was due to a typo in the /etc/fstab after the restore.

I have updated the original post with the missing information that resolved the problem.
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Re: Problem with grub-install on Dell Vostro pc, after a res

Postby Head_on_a_Stick » 2020-01-24 16:08

ole_thor wrote:
Code: Select all
for i in /dev /dev/pts /proc /sys /run; do mount -B $i /disks/Bkp-Root$i; done
chroot /disks/Bkp-Root

You can save effort next time by using the arch-chroot command (from the arch-install-scripts package) to mount the API filesystems & chroot in.

Anyway, please add [SOLVED] to the thread title to help others who may encounter this problem.
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